C
Advantages: Was really concerned ordering the handset from China after reading some reviews but this has surpassed all expectations - arrived in 11days from hong kong warehouse which is quite good I guess. Works well with Uk network (Tmobile, though O2 and gifgaff are not supported - check the frequency before ordering to make sure.) Really good value, definitely recommend, fast shipping, though the tracking updates are slightly delayed.
Limitations: None, brilliant device!