I used my credit to get some classics that I couldn't find in the upload section only to see them uploaded a little bit later... with far better quality. My advice is to use the ebooks section as your primary source for classics; only buy from Connect if you don't find something here that you want to read right now (because if you don't want to read it right now, it will show up eventually, with no DRM, with a more pleasant format, and probably with beautiful illustrations). And don't forget that you can request books that you are interested in in this thread:
https://www.mobileread.com/forums/showthread.php?t=10290.