Counting the number of posts in the bugs and fixes thread to show how buggy 2.1 is, isn't an accurate way to judge it. The majority of those posts are about 3 or maybe 4 issues being repeated over and over. The one that is probably discussed the most isn't even a problem with the leak, but a problem with a third party app.
The other 2 "major" problems are that gmail won't show embedded images and people have to sign back into gmail after a reboot. The embedded images problem is a global Android problem with 2.0+ from what I understand. Complaining about it in the 2.1 leak is the same as complaining that bluetooth voice dialing won't work in 2.1. Having to sign back into gmail after a restart....oh boo hoo.
It is a minor annoyance for people that restart their phone all the time.
The only real legitimate problems, IMHO, that people can complain about are the signal meter and the links in some apps. This isn't to say that the phone gets weak signal, but that the meter shows weak signal a lot. The only reason this is a problem is that it can actually burn through the battery a little faster. The link issue is annoying, but plenty of people have found ways around it and it isn't 100% in all apps. I only have one app (urbanspoon) that has the issue.
With all of that said, the only issues I actually have are the link issues in that one app and the lack of embedded images in gmail. Everything else works perfectly and I am extremely happy with 2.1.