Blu Vivo 4.3 seems to be available in the USA: BLU VIVO 4.3 Android Smartphone (Unlocked) #2-BLU-D910A-Q-BLA-01 - Expansys USA
with superamoled and MT6577
the version is D910A, the other one will be D910 (or D910i as gsmarena notes)
HSDPA 900 / 2100 - D910i
HSDPA 850 / 1900 - D910a
What is the impact of these bands for both phones when using in Europe?
ed: found it in http://en.wikipedia.org/wiki/UMTS_frequency_bands
D910i is for Europe, Asia, D910a for the Americas.