Puerto Rico - Telus 1.04.05V
This island is full of dead zones if you don't have Centennial as your carrier. Thankfully, Sprint roams on Centennial's 3G network in
PR if out of range from a Sprint tower. Using this Telus Radio I average 1 - 2 more bars than stock Sprint radio and heat is greatly reduced as a result and I RARELY ever get sent into roaming. I read somwhere in these forums that Telus puts a lot of development into their ROMs as it seems that Canada is also full of fringe areas like Puerto Rico.
I haven't really tried the latest Sprint or VZW radios though. Kind of taking the "if it ain't broke, don't fix it attitude" towards flashing my radio.