I was rooted and stock froyo for a long time. The only problem I had was memory leaking. It always aggravated me when I would have 200 MB free and it would consistently drop to below 100 MB when I would not be using my phone.
CM has so many performance features built in my phone runs at a completely different speed than rooted stock. Knowing how fast my phone was on CM will probably be the only reason I go back.
2.3.4 doesn't seem like it changes the experience from Froyo. I have noticed the memory leaks are much less. The screen changes are crisp and overall the phone is running great. It's just not as great as I was set up before.
That is what is great about Android. I can love CM and you can love rooted/stock!