I had the samsung t409. the voice quality was bad, it kept dropping off my router, lots of dropped calls, did not work with bluetooth. the call quality on bluetooth was horrible and would sometimes drop the call.
Wifi range on the samsung was maybe 15ft to be reliable. Oh yeah, and regular RF reception was abyssmal compared to my other tmobile phone, moto v360.
The curve is not perfect, but it is superior to the samsung in nearly every way. Except battery life. However, I loaded the newest os and it appears the battery life is better. Not scientific enough to be sure though.