Please understand we were a paying Enterprise customer - not the freebie Community Edition. The support we received was atrocious. If there is any modification to the software, which they encourage, you are done with support. Third-party software basically nullifies support as they will want you to REMOVE any 3rd party software if they decide to troubleshoot an issue. There is NO timely support. Every response you get takes days. Woe unto you if you forget to include an obscure detail because you will be asked for it and that resets the "days" clock.
When the ultimate resolution of a series of problems with the software was to upgrade a version - WHICH ODOO ALONE CAN DO - Odoo reported to us that they could not update the version, effectively leaving us stuck on an old version with problems with absolutely no resolution. Only Odoo can upgrade you so we were effectively stuck. The Windows equivalent of saying that you cannot upgrade from Windows 98 - you can probably just start over.
I reached out every way possible to Fabien Pinckaers (including Tweeting) to help - there was a flurry of attention and then it all just died.
A few months before the renewal was up, I got a call from Odoo. Some poor newby college kid wanting to get some quotes on how happy we were. After telling him the situation, his comment was something along the lines of, "Yeah, upper management just doesn't care about the clients." His words - not mine.
Ultimately, we wasted about $20k worth of capital and about 18 months learning these realities. Review collected by and hosted on G2.com.