Really can't imagine why I would need LTE speeds on my phone. Tethering would be the only reason, and given the data caps the extra speed really isn't worthwhile. Why do I need Internet so fast that I can exceed my monthly data cap in 45 minutes? Makes no sense.
3G speed lets me stream audio (even video if I want), and does a passable job with tethering as long as I'm not trying to stream HD video (see data cap issue above). 3G also gives me a terrific battery life with the iPhone 4.
Eventually the plans will catch up with reality, we'll see 20-50GB caps on LTE plans in another year or two. The iPhone 6 by then will have a more efficient LTE chipset, and newer battery technology to allow it to work smoothly. I'd rather wait and get a good, workable LTE solution than deal with the compromises now.