Ok – I tested out TTLS with my wife’s Mac the other night… She’s been running ever since using it without complaint. I only changed the checkbox from PEAP to TTLS and unchecked the MSCHAPv2 box (in the TTLS properties), so it would use PAP, as suggested by the university site you pointed to above. I’m guessing it would probably work with MSCHAP too, but I haven’t tested it yet. Of course, I didn’t have any certificate issues, since it was already a trusted certificate from when I used PEAP.
At any rate, we’ve just started converting clients over to WPA2 Enterpise at my work today, using PEAP to minimize what has to be installed on the client machine. So far, so good.