I have looked into this a few days back, and it seems the TMobile US version is the best. But if you can wait a little longer, the LG G3 is out which on paper, is better than the S5.
3gb RAM (there is a 2gb RAM version)
Quad HD display (4x than on the S5)
3000mAh battery (user changeable)
Built -in Qi wireless receiver and NFC on the REMOVABLE battery cover (this is by default, unlike crapsung that sells the Qi/NFC enabled battery cover, which makes the phone thicker, and very difficult to find a case that fits)
No Knox to worry about.
Galaxy Tab Pro 8.4 - better than Tab S
Note 3 Stock ROOTED TW 4.4.2 (XXUEND5) -returned for faulty screen, N900T - returned for faulty screen and buzzing speaker.
Note 2 - Sold
S4 - FNB8 Stock rooted
S3 - TW 4.3 Stock rooted (Still awesome phone)