Ours is a "mixed marriage" - the Blonde has an iPhone4, I have a Droid Bionic. We are VERY much a Mac family in all other respects: a couple MacBook Pros, an iMac, iPad, and various iPods. The thing that swayed me towards the Droid Bionic was the 4G (I had already owned an original Droid for two years). We were in the boonies at the time, and had very little coverage of any kind, so it was a leap of faith for the 4G. I've now had the Droid for about 6 months, and we have had 4G about as often as 3G in our travels. There is a BIG difference in the speed, and we use my Droid as our hot spot... no DSL, no cable modem, and we don't count on finding wifi along the way; we just make our own.
I have been delighted with the Droid AND the 4G. Let me clarify that: WE have been delighted, since Joan generally uses the iPad and/or a MacBook Pro, and my Droid is her internet source, too.
There are some differences in the apps and their availability between her iPhone and my Droid, but it really is pretty insignificant. I get all the weather, radar, and navigation I need on the Droid. There have been a few instances where she has had an issue finding a place in the land nav mode on her phone, that I just speak into the Droid and it pulls it right up, including directions.
Just like Macs and PCs, it seems that these phones are more alike than they are different. The approach to getting the info out of each is a bit different. For ease of use, the iPhone is easy and seamless; the Droid seems to be more adaptable.
I don't think there is a lot of difference between the Razr and the Bionic, other than thickness.
If you truly don't think you're going to be in an area that offers 4G, the difference is pretty minor. If you have the opportunity for 4G and use the phone as a hot spot, the Droid is definitely the choice. If you're just using it as a phone and a solitary device, again, not that much difference. No doubt that the iPhones do work more seamless with other Mac devices.
I didn't think the whole 4G thing was going to be much of an issue, but it really offers great speed for internet connection. Most of the time with 3G, we see between .5 and 1 mg; with 4G it is between 5 and 14 mg - a significant difference.
And a couple weeks after we got to the Tropical Tip (sometimes known as the end of the US), we went from crappy 3G to outstanding 4G service. Equipment upgrades are happening.
Hope that helps.
Best wishes,
Jim B.