I am on my second Droid. I had the original for about 2 years. I really liked that phone, but it was getting old and slow.
I was eligible for an upgrade the same week the Bionic came out- that's what I have now.
Night and day difference.
My DH got his first iPhone 1 week before I got the Bionic- so we have been doing a lot of comparing. He previously had a regular old cell phone. This is his first leap to smartphone-land! (and he is chugging the Apple kool-aid. The iPhone just completed his conversion.

)
He envies my screen size! It is significantly larger than the iPhone, but not so large that it doesn't still fit easily in my purse or back pocket of my jeans.
He likes that the iPhone syncs with iTunes. But I think that's a drawback. He cannot put anything on his phone that does not come through iTunes.
It seems like some of the apps I have for free- cost a little on iTunes.
I love my Droid Bionic. I was looking at other droids as I was preparing for the upgrade. The X2 was pretty good, but I really didn't like the HTC phones or Samsung. And from reading the Android forums online- I think a large number of people with those phones have more issues with their phones.
I think Motorola makes a nice phone. And now that Google runs Motorola's cell phone division- all the better since I use Google calendar and contacts and email. (although you can do that on the iPhone too I think)
Bionic has 4G. It is VERY fast. No iPhone has that yet- I know the 5 will, but it's not out right now.
One more difference. The iPhone does not have a removable battery. This is a topic of debate in my house. I prefer being able to carry a charged back-up battery with me to swap out if necessary- like in WDW for long park days or other places where I might not have easy access to a charger. DH thinks it's nice not having to carry "accessories."
Lastly (and not meant as an insult) the guy in the Verizon store told me that the iPhone is great for people who have never had a Smartphone before. But the Droid is for those who are used to Smartphones and know what to do with them. Droid has much more to offer. But the iPhone is a great "all inclusive" package.
So- hopefully those are a few things you can consider as you make your decision. Let us know what you choose!