T-Mobile points out that its Nexus 6 has no carrier branding or bloatware
As it turns out, a leaked internal AT&T document revealed that Motorola had loaded incorrect software on the AT&T version of the Nexus 6. This forced the recall of an initial batch of Nexus 6 units that had been sent to the mobile operator. It is believed that Motorola's slip up has something to do with AT&T's added bloatware.
If you're a T-Mobile subscriber and thinking about purchasing the Nexus 6, have no fear. The handset will be bloat-free and will also not have any of the carrier branding that the AT&T variant has. The T-Mobile Nexus 6 will be strictly a stock Android affair, the way that our ancestors envisioned the line in the first place. You have to wonder what AT&T was thinking, opening itself up to criticism from its customers, Android purists and from T-Mobile.
source: +DesSmith via AndroidAuthority