HSPA + is recognized as 4G by the International Cellular Standards Committee because it is fourth generation technology. And phones can tell the difference. 3G in Europe is not the same as 4G here, at least where I've been. I've been on 3G there and tested the network and it was no faster than 3G is here on average. With T-Mobile 4G, I get 18 mps download regular. My nephew was visiting this weekend and he has Verizon LTE and he was only getting 15 mps with a full signal.
I don't know any 3G that can pull down the kind of speeds I get with HSPA 4G. My findings compare favorably to tests PC Magazine did last year where they concluded T-Mobile's HSPA 4G was about as fast as Verizon's LTE in every part of the country. So yes, according to the data speeds and the folks who name the bands HSPA 4G is a form of 4G technology.
I love HSPA 4G; my complaint is that T-Mobile just doesn't have enough of it and when you leave a 4G area you fall back on EDGE, where the fastest speeds I've gotten were 245 KPS down. Normally, I get less than 50 where I live.