Installed Froyo on an HTC Magic last night. Some trial and error involved, but I am amazed at how fast it runs. Every now and then there is a little lag, but nothing that the user of a Magic wouldn't already be used to. I've yet to run into any FC, but then again, I haven't really hit it that hard (still running off WiFi since it's for someone else and I need their SIM to real-world test).
Just follow the directions on the Cyanogen Wiki, don't improvise, and be patient.