I own the MetroPCS galaxy mega. I'm a MetroPCS subscriber. T-Mobile bought MetroPCS and MetroPCS is using T-Mobile's 4G network. So, technically, I'm using a MetroPCS mega on T-Mobile.
That said, I live in NYC and I normally get between 25 and 30mbps download and around 15mbps upload. I've gotten as high 42mbps down and over 20mbps up.
I haven't experienced any dropped calls and I've only experience occasional drops from LTE to HSPA+ (and when on HSPA+ my data speeds are around 15mbps down and 2mbps up). I've never dropped below HSPA+ in NYC.
Sent from my SGH-M819N using xda app-developers app