I think that support here is very good but it could be better so I'm open to improve if some think that is not good enough.
As far as I know, there isn't other system where the direct creator of the thing reviews each issue and if is needed dig into your FTP and fix the issues for free or without asking for a renewal or something. There could be a lot of things in system like this, some of them are just standard things like a missing library but sometimes there are bugs regarding certain functionality or maybe bugs due to the nature of all the dependencies in system like this one and how them interact each other.
But take for sure that no matter how the problem is there will be help to at least pointing out to the right direction regarding your server setup and in some cases I personally debug the system doing extensive test direct in the websites and perform the needed fixes at script level. Most of the bugs fixes here are thanks to that I actually debug a lot the installations, that is because there is no such thing like a true standard PHP installation and there are many things that could fail. Just last week I found a PHP version where the ternary operator didn't work with NULL typeset so I patched it so no one else will have that problem, that won't be possible if I didn't debug conflicting installations.
Software is always like that and if you notice Chevereto is a very mature system and it gets updates like each 15 days so try it with confidence and I encourage any current client reading this to feel free to give their feedback about support and the system overall.