The PPC-6700 was the first Windows Mobile 5 phone to hit the US market. I consider more recent iPhone series, android and Microsoft phones to have made evolutionary improvements over the PPC-6700. Obviously, there have been improvements in size, performance, Operating Systems and applications but the basic functionality and uses are similar.
We have upgraded from the PPC-6700 but have a grandfathered Sprint plan with free unlimited data. Sprint won't let us upgrade from our current HTC Touch Pro 2s without going to a plan that will cost approximately twice as much. I should probably thank Sprint for keeping me from wasting more money on trinkets that I don't really need.
Unfortunately, I think I'll never have any trouble making the case (what's having a better memory worth?).