Speaking with out any true comparison, I've never had much complaint with the browsing speed with Sprint on the non-EVDO side. It does what I need it to do at a pace that doesn't leave me cursing my BB. I too live on the edge of an EVDO service area, patiently waiting for the expansion of it, but not ready to jump ship because the process moves slowly.
So my qualifier is that, in my experience in my corner of the world, non-EVDO browsing speeds with Sprint, while not phenomenal, are sufficient. I think it does come down to coverage, as stated above. If the entire state is EDGE, and you crave that speed, then that doesn't seem like a bad reason to switch carriers. Early termination fees, like speeding tickets, are one of life's little inconveniences. You'd probably be waiting for quite a while on that Sprint 87XX, anyway