Just got the Note 3 [SM-N900T] from Tmobile, they locked the bootloader on it, along with the ATT version that I bought as well [SM-N900A], both are locked. The policy with Tmobile says that they won't unlock the SIM for the first 40 days after you purchase the Note 3, the sales reps said that we could probably pay other folks to help us unlock in prior to TMobile stepping in.
The international version of the Note 3 [SM-N900], that I bought from onthegosolutions, was really easy to root, was sim unlocked and bootloader unlocked as well (only complaint is not having the high bandwidth from LTE here in the states).
Did a side by side on the TMobile LTE network, the speedtest results were started off at less than 1mb up/down, last test ran at 10mb down and 5mb up, while the international version typically runs 4 - 6mb down on ATT, the N900A's LTE seems to be running about 10mb right now as well, so you aren't missing much in performance, when compared to the hassle of dealing with a locked bootloader and the lack of root, etc...
Hope this helps...
Bob