I have been working with Nextel for a couple of years. I currently have the i580 and i started out with the i730. Both phones have been very good to me...depending on where you live, since the merger of Sprint/Nextel, the coverage has expanded. I know there are several areas like in Nebraska that doesn't have good coverage for nextel. But if you want a good strong phone, that is the way to go. The i730 is not something you want to drop in the toilet...but if you were outside and it got rained on, you are ok. the i580 you could drop a cinderblock on from 2 stories and it would more than likely survive. the i580 is mostly rubber, and it's a designed contractors phone. I had a co-worker drop his i315 (another contractors design) into a cement mixing plant drum, pour it into a cement mixer, and got it back still working. 2 weeks later he accidentally ran it over with an endloader. it still works to this day. When it comes to AT&T, Verizon, and straight Sprint, you will not find a good contractor style (bulletproof) phone. If you want more information on this kind of stuff let me know.