Keep in mind Dropbox literally got its start with adding the sync icons in Finder when Apple said it could not be done. The entire company was essentially based on their ability to make a better user experience through a tighter integration with your files then was technically allowed at the time. I'm not saying you have to find that acceptable but it is what it is and its the reason why millions of people have heard of Dropbox and proclaim its joys.

Anyway both things you mention are bugs even if you find them frustrating. The original poster was having issue with the option to turn off the Finder integration but the option was put there so you can control it. The only reason you can't access files with more than fifteen in a folder is clearly due to a bug in the beta.

If you want to say that a company the size of Dropbox should never have bugs of that scale even in their beta, then I would point at several of Apple's broken iOS updates (bricking phones, etc.) or Samsung's recent Galaxy Note 7 fiasco as evidence that much larger companies ship software and hardware that isn't in beta and has undergone much more due diligence with catastrophic bugs.

Anyway I don't use Dropbox really but I felt compelled to comment because I couldn't understand how you could say you expect bugs but don't expect the reported bugs in a beta.