Well , me being a great fan of e107, all i can say is that , The bugs that we see are of the new development version. e107 is comming out with version 7 of its CMS and its truly a renovated effort on its part.
About the user DB , well most of the people don't know about e107 still , i got to know about e107 from a user here spacewaste, i saw his website, loved the CMS used and checked it out further.
If you are having problems with the plug-ins then i suggest you see which ones you are trying to download. There are plugins in development for version 7 and plugins already made for version 6 , either ways i guess the version 6 plugins wont work with 7 because of change in the system code.
I tried to use themes made originally for 6 with 7 , and they worked like a charm, but themes made for 7 dont work with 6. Well all i can say is that not all CMS out there are perfect, some have things that others dont. I tried PHPNuke, MKPortal and now e107, havent gone to try mambo and others but i am shure they are pretty good in their own way.
Regards
Dhanesh