My husband had a Droid and loved it. Then he got an iPhone when he changed jobs and likes it so much better than the Droid. I've only had an iPhone - never had a Droid - and love it. It is annoying to not be able to see flash video but there's an app for that I haven't bothered to get.
In response to Jennifer's answer:
iPhone's have allowed tethering for awhile now, you just have to make sure you have the right data plan. This is true for both Verizon and AT&T.
I can also access my gmail account on my phone, and my yahoo account, and others I can't name without looking right now. All you have to do is take a couple of minutes to set it up. I can have my inbox show both accounts at the same time or I can look at them separately.
You don't have to sync solely through iTunes. You can also use the cloud service but since I'm cheap, I don't want to pay for the extra storage I would need to keep my music, videos, and photos synced. I do use it do keep my calendars, notes, reminder list, etc. synced and current between my phone, iPad, and Mac.
ETA:
I don't have Siri - don't have a 4S - but my husband does and it doesn't seem to work too well for him. But FaceTime is so cool! It's video chat between apple products over wifi. So if I have a wifi connection, my kids can use my phone, iPad, or Mac to video chat with my husband on his phone (over wifi) when he's traveling. If the device doesn't have a phone number, you call using their e-mail address.