I had an IMT 550, it lasted bout 3 months and crapped out(screen would stay lit, no data). The shop I got it from readily exchanged it for another, thinking it was a lemon. 6 weeks later it crapped out. I took it back again, they said they'd stopped carrying them because they were having so many problems with them. I LOVED the functionality of them, but for me, they wouldn't hold up.