The US Cellular UTstarcom UM175 modem from US Cellular works fine with the KT2 router. Kyocera techs claim it wouldn't work, but after I loaded the Smith Micro software and initialized the modem on the US Cellular network I then just plugged the USB modem into my KR2 and rebooted everything and it works great. I had a Verizon 720 USb for the past year but lately the speeds have been terrible. I was getting .7 - .8 downloads usually but recently it has been down to .5 (one nice clear day last week it was down to .12 (dial speeds)). The UM175 is getting 1.2 - 1.3 down consistently.
I have the same data card from US Cellular. I use the Cradlepoint MBR1000 WiFi router.
I pulled out the Verizon data card and replaced it with the US Cellular card and it worked right off, only much faster than Verizon.
I had a Pantech card from Verizon and found that it was MUCH more sensitive than the US Cellular Pantech card. If I didn't have a repeater I wouldn't get a signal with the new card.