I can tell you that, quite honestly, I am not switching to 4e. I did not switch to 3.5. I played first edition for years and years. Second edition I played briefly when it first came out, but largely ignored it. I came back to D&D with 3e and have been happy playing that ever since it came out. I found 3.5 to be unnecessary, and I find 4e to be even more unnecessary. I have not bought a WotC D&D book in ages (with the one exception of the Magic Item Compendium). I don't see a need or reason for me to purchase a new edition. I know why Hasbro/WotC is doing it, I just don't agree with the profit motive in this case.
I am happy with the version I am playing. When I am done with my current campaign I think I am going to switch to GURPS, or maybe play some Traveller. About the only way I am going to get 4e is if someone buys it for me.