I've had the Huawei E5756 for 3 days now and am favourably impressed. It is supposed to be twice as fast as the first generation MiFi and that is confirmed by my experience so far. With my previous E586 MiFi I typically used to get, at home, average downloads at around 5 to 6 Mbps, occasionally as high as 9 or 10. With the E5756 I am averaging 10 to 12 Mbps, sometimes as high as 16 or 17 on both my phone and my laptop. I have not taken it out on the road yet but this will certainly save me a lot of time downloading stuff to my lap[top when I'm out and about..
I was surprised to get the higher speeds on my phone because it is a Samsung Galaxy S2 and I didn't think this phone would be compatible with DC-HSPA+ but whether it is or not, download speeds are certainly around twice as fast as before.