Hsupa Hsdpa Difference Will I Notice A Different Between A 3G HSDPA 850/1900 MHz And 3G UMTS / HSDPA / HSUPA 900/1900/2100 MHz Cell?

Will I notice a different between a 3G HSDPA 850/1900 MHz and 3G UMTS / HSDPA / HSUPA 900/1900/2100 MHz cell? - hsupa hsdpa difference

I think to a new phone, a Sony Xperia X1 for sale. There are two different versions (X1A USA) and X1 (UK). The X1 has been published, and the U.S. must be released in the near future. I do not understand about the frequency. If I to buy the X1 (UK version) I notice a difference in the performance of EDGE or 3G? What will I lose? What would be your recommendation? Please reply only to serious people. Thank you.