For more info than you will ever sift through about the T608:
www.t608.comwww.sprintpcsusers.com (Includes a forum dedicated to the T608.)
IMHO, the firmware is stable enough. I\'ve never really owned a comparable handset, though. Upgraded from a 2000-vintage Ericsson to the Treo 600 (which also crashed/rebooted occasionally) to the T608...which crashes occasionally.
After a couple of conditioning cycles, even stale batteries have provided me with about two hous talk time. If you live your life on the phone, you\'re going to need a bigger handset with a less diminutive battery.
The data plan issue is still an open question. I had no trouble
transferring unlimited Vision from my Treo 600, but a few people have reported being unable to get unlimited Vision when adding the T608 as a new line.