Another Uplink provider I found was GeoArm. Havent used them though, but it seems to be hard finding reviews for monitoring companies in general. Looking for reviews on cell monitoring seems even harder.
Gotta watch all of these companies to make sure they are actual physical UL listed central stations. They cant get that cheap per month for no reason! (although I find it quite interesting that once you start doing something outside the box, like cell monitoring instead of POTS, all of the "discount" monitoring companies end up at non-discounted prices)