So Network Vision is slowly but immensely improving the overall experience on Sprint. Luckily living in the Bay Area a large amount of this work has already begun and is continuing each day. For a while I was seeing improvement and loved Sprint for every moment. At the begging of this week all of this suddenly disappeared, being an avid reader of this site I assumed it was an upgrade and just continued on with my day. Now it's near the end of the week and no improvement whatsoever. Basically I would like to know if this is a device related problem (iPhone 4, iOS 6.1, PRL 51094) or if it's an network upgrade which I'll just ignore.
Yup! Sprint reused Clear PLMN to give TMobile roaming higher priority. If you notice next to LTE on the notification bar there is a small "R" and SCP sees it as Clearwire B4 (basically that's the PCC your connecting too on TMobile)
Also, you see it as Sprint because all roaming is going through Sprint's back end that's why the ping times are affected adversely.
Btw, nice speeds!