Odoo (OpenERP) vs SAP
As a former employee of a company implementing Odoo (OpenERP) I had some knowledge about it and probably I am one of the few who had experience with both Odoo and SAP. To be honest, I felt in love with OpenERP about 1.5 years ago. At first, it looked astonishing, and now it looks even more appealing. There are plenty of features that everyone will like. It feels simple and easy to use and in most cases the necessary training for the end-users is lower than most business solutions.
Odoo is gaining fans which is critical success factor for open source project while in the same time SAP is growing, but in minor steps. So probably you will think why I left Odoo environment and went to SAP which feels old, ugly and has steep learning curve. The primary reason was the limited out of the box functionalities, bugs and absence of opportunities for heavy specialized financial professionals like me. Let me try to show you some of my thoughts regarding this comparison.
Out of the box functionalities
Behind SAP Business Suite there are 70+ millions lines of codes compared to Odoo's 0.150 millions presented on Odoo Open Days 2014. One interesting fact, that is not so widely known is that SAP Business Suite is with open source code which means that you have the ability to change the core applications at your own risk. It also means that if you don't like your consultant, you can switch it without loosing the source code of the custom developments.
Speaking about functionalities, I had an unpleasant experience with several customers during my 11 months journey with Odoo as a functional consultant. There were many processes which we were not able to implement without further development in Warehousing, Manufacturing, Purchasing, and Sales. I am not going to speak about Accounting as it was too far from my expectations based on my background in Financial and Management Accounting. Accounting will be one of the biggest projects in version 9.0 for Odoo, so probably we will see some improvements here.
It is not a good idea to compare SAP Business Suite with Odoo as they are prepared for different types of customers. Business Suite is for the biggest companies in the world like Fortune 500. However, Odoo is for SME companies. SAP has other product which is highly competitive in SME market, and it is SAP Business ByDesign. It is a cloud solution which is offered at a very reasonable price, with rich of functionalities and in the same time comes with a plenty of tools for rapid and efficient deployment.
Backward compatibility
There is one key reason where SAP excels and where Odoo is usually a substantial disappointment, especially for bigger companies. SAP and their products are maintained and developed with backward compatibility in mind. SAP Business Suite is full of code which is two + decades old and which is working flawlessly with new versions. However, this is not the case with Odoo. Every new release means migration of code and data. If you use the out of the box functionality, you should go for Odoo Enterprise Maintenance Contract. The contract will cover bug-fixes and migrations to newer releases.
If you have custom developments it will be a really painful task. We are not only speaking about IT costs for consultancy and re-engineering, but also the business will put a lot of effort and frustration for the tests of the "migrated" functionalities. It is known fact that no matter how much efforts you put on testing, in many occasions you will find errors in your production system. Production is the best environment for "testing" and always will be.
My point here is when you choose Odoo over other Business Solution providers you should always keep in mind how much cost will get the maintainability of the system. And you should be careful about the hidden costs including the employees' time that you will be invested.
Pricing
Odoo Cloud solution costs 12 Euro per user and app. This means that if you use Sales, Marketing, Accounting, Project, Purchase, Warehouse, Manufacturing and Human Resources it will cost you 96 EUR per user/month or 1152 EUR annually (as at 07/2014). From what I understood the same pricing will apply for the on-premise solution if you look at the Odoo Enterprise Contract. It is highly recommended to go with it otherwise you should have very good technical consultant which will again incur some costs to you..
As mentioned above SAP Business ByDesign is on-cloud solution which has very competitive pricing. Their offers starts from 10 EUR for self-serving users up to 179 EUR per user/month for those who will use most of the system. The most expensive user type will probably be needed only to a few employees. ByDesign is available only if you use minimum 10 Team or Enterprise Users. Team users will cost 79 EUR or your minimal monthly cost will be around 800 EUR.
In terms of pricing, Odoo offers cheaper options to smaller business as they even have free version for the on-cloud solution up to 2 users. One key fact is that Odoo is not accepting custom code on their cloud solution. This means that if you need custom development (which I think is very likely) you should go for the on-premise solution hosted by you or partner of Odoo. In case you have more than 10 users it is highly debatable which solution will cost you less in the long run especially counting the involvement of your employees.
Bugs
Bugs were a significant issue in releases of OpenERP 6.1 and 7.0 versions where there were tons of bugs interfering the productive usage of the software. This was really irritating for customers for which I was responsible and for myself. In the next versions starting from 8 it is stated that this problem will be less and less critical as every new core functionality will be firstly released for on-cloud platform where it will firstly be tested additionally by the customers. I hope this will be a good move as it will put risks on the on-could clients.
SAP Solutions in the comparison are much more mature and backward compatible. That maturity will help you to avoid many issues you may have. For sure SAP have and will have bugs in the future, but they will not put your business on the cliff. They will be primarily minor ones.
Business Experienced Consultants
As Odoo is still not a mature product, you will hardly see experienced consultants with domain business background. Most of the Odoo consultants will be wide specialists and do consult for all the applications with some exceptions to Accounting. The functional consultant opportunities for business people are limited, and the income will not attract them to Odoo. The reason is simple. Odoo customers will be mainly companies with 5-20 employees which will not require advanced industrial knowledge and professionals with experience and high payment expectations.
It is a widely known fact that for better or worse, Odoo is driven by IT geeks who feel excellent with it. It is a perfect opportunity for them because their skills are appreciated a lot in this maturity stage of Odoo. Perhaps you will experience in some cases how software engineers will try to convince you that they are good in business consulting.
Conclusion
Odoo is very attractive solution which will suit very well to some companies. If the out of the box functionality is enough for your needs, then go for it! Probably you will be very satisfied. But keep in mind that behind the shiny surface it can lead you to a very unpleasant path. You should be very careful with the custom developments as they could cost you a lot in the long run. Try to be objective, meet other companies implementing different software. Ask for demos where you could see exactly how your business processes will look like. You should also ask for the disaster recovery plans as they are really important once you realize that you rely heavily on your ERP Solution.
Update 28/09/2015
I recommend you to read the comments below as there you will find precious real-life experiences.