Well, Cricket is AT&T. AT&T owns them, and makes all the decisions with regards to what Cricket carries. It is kinda cool walking in their stores and at least seeing WP stuff. I put three family members (non-techies) on 635s there, and all are happy.
I, however, am not happy. I bought a 640 on the day that Cricket released it (last April). Nice phone, pretty blue shell. An interesting piece of promotional material next to the display from Microsoft. Cool! Says my 640 gets a free upgrade to Windows 10, when available*. I look at the asterisk and it says *late summer 2015 release. I'm a happy camper.
9 1/2 months later, no signs of W10M in sight. When Microsoft announced in December that it would not come until 2016 first qtr, I bailed and went to Android. That phone spent the equivalent of half it's life waiting for an upgrade that didn't come.
THIS IS WHY W10M HAS TO BE RELEASED TO OLDER PHONES THAT HAVE THE HARDWARE TO HANDLE IT. Those of us that post here are the tiny, tiny minority. The bulk of WP users will say..."where is my shiny new operating system I was promised? NEVER AGAIN!" Microsoft will never, ever have a chance to sell those people another phone. They spent a lot of time pushing the low end stuff out the last two years, they cannot abandon those users they just recently brought into the fold.
It's all a shame, cause WP had unlimited potential, and Microsoft continues to smack itself in the forehead and fritter it all away.