The 12th can't roll around fast enough for me, that will be the first major upgrade I'm going to do for a series of django sites built in the last year or so, and I'm very curious how well that upgrade process will go.
Upgrades are the sticking point when it comes to frameworks, I hope that django will show that I made the right choice in that respect.
"./manage.py test" is your friend. Deploy the update on a separate server (or your development box) and run every conceivable test. Update your test fixtures with data that resembles production data and use it for testing. Do stress testing on a regular basis and monitor your machines (I love Munin for that) closely.
Also, remember to make tests that are performance-dependent, so any relevant change is flagged (you can kind of self-scale your test timeouts by using "getting item A does not take more than twice as long as getting item B").
Please give the RC a try - we put it out specifically for people like you, and we try really hard to ensured backwards compatibility. If you find bugs now, we can still fix them before the final ships.
I upgraded to Django 1.2 on our internal tool set, and then used it for our new site we just launched today. Granted, our internal user base is only 10 staff, and our sites are only in the thousands of visitors but no real issues when upgrading or using 1.2.
The Django devs are very good at keeping bugs out of the way, even within the trunk and as long as you follow development, it's easy to either avoid the bugs, or patch them with the solutions pre-trunk-merge.
Upgrades are the sticking point when it comes to frameworks
Yes. They even cause the language to get sticky! I think Guido's moratorium was smart -- things need to be tightened. While it's somewhat trivial, having many different Python interpreters is an annoyance. I can't use NumPy, SciPy, and MatPlotLib on Python 3, and I don't have good Unicode with less-than Python 3.
I used to do Django development just around when 1.0 came out. Even though the new features section doesn't seem huge, the release docs for 1.2 kind of makes me want to revive some of my old projects again!
Upgrades are the sticking point when it comes to frameworks, I hope that django will show that I made the right choice in that respect.