Does the bumper (or other cover) fully "resolve" the antenna issue?
I would never use my iPhone without a cover for grip/drop protection (use the Incase Protective Cover on my 3G). If it fully resolves it, then it would be a non issue for me.
I've compared my 3G to the 4G several times at the local Apple Store. Love the relative blazing speed on the 4G and the multitasking is a big plus for me. I can live with other issues assuming resolved by firmware/software updates.
I expect to be notified at any time that the 4G I reserved at my local Apple store has arrived and am debating on canceling and waiting.
3G, iOS 4, Windows 7