Well fair is fair, I got my white bumper today and I really like it. Of course the plug on the bottom is the smaller size, but I went on eBay and just replaced my two older "fat" USB cables with OEM Apple ones for about $5 a pop and I still have the other slim one that came with the iPhone 4.
This bumper is a MUCH tighter fit; it BARELY moves around, but you really have to try to notice it, unlike my black one. Who knows if it is because it's a later production or what - but it fits better. I also like the contrast between black and white. Fortunately, I bought this bumper BEFORE Jobs announced his giveaway and they became unavailable on Apple.com, because who knows when you'll get your bumper when they're giving away 3 million cases (actually less, they'll be refunding those with cases already - like me). Finally, proclips is coming up with a car holder/charger like my old one so for now I'm using my iphone 3G holder without a charger and just using a regular USB type to cigarette lighter to charge.
My advise - if you have a bumper, try it out for a few days, just be aware, many accessories will not work wth the bumper on.