The reason the iPhone works more smoothly than the Droid isn't because the iPhone doesn't multitask and it's not because it has lower resolution. It's because Apple chose to make the fluid interface a priority and they made sure the software was written that way. Apple is a stickler for little details like that. It uses OpenGL to render the graphical interface, and the droid does not.
I like the Droid, and I liked my iPhone too. Right now I'm using the Droid because it has more of the features I like today than the iPhone does. So all the people that come out of their holes to shout, "if u dont like ur droid go bak to ur iphone" just need to crawl back into their little holes, because you are just as much of a "fanboy" as the iPhone users are. I'm not a fanboy, I use what's good, and change it up once in a while to keep it interesting.
The resolution argument isn't valid because the hardware on these phones is MORE than capable of rendering fluid graphics at the resolution the Droid has - it's a matter of writing software to take advantage of it.
The multitasking argument isn't valid either, because anyone who has a jailbroken iPhone can tell you that you can install Backgrounder and run Pandora and whatever else you want in the background, and magically, it works great. The browser still flows smoothly as do all the window animation and transitions.
I'm running my Droid at 1 GHz with the lowest overhead I can manage, and I'm not going to fool myself into thinking the graphical interface is on par with the iPhone. That's not the Droid's strong suit. That doesn't make it a bad device by any means.
And to all those that say their Droid is as smooth as butter - good for you. You haven't used an iPhone long enough to see the difference. That's a gift. Keep it and enjoy the Droid more for it!
Now that I've said all that, I'll be sticking with Android until Apple can allow some basic things on their device without the need to jailbreak.