Indeed. EDGE is fine for some things, like if you're simply sending IMs/emails, but if you're surfing the net, downloading apps/media, accessing apps, streaming music, etc you'll really notice a difference.
It's hilarious to me that people make fun of T-Mo because they're just using a beefed up 3G network and it's not "true" 4G (even though no carrier currently has TRUE 4G), and yet we get comparable speeds without having to sacrifice battery life at all. I've seen how Sprint does it. You actually have to "turn on" 4G connectivity much like you turn on wifi on your phone. With 4G connected, battery life is severely sacrificed. T-Mo users get the best of both worlds: fast speeds AND good battery life.