There are several that come to mind. The first is choosing a keyboard. This isn't just aesthetic, I use Smart Keyboard Pro on my Android, and it has a multitude of options, best being auto-text, like BlackBerrys have, where it automatically changes words to predefined words. "u" --> "you" for example. This is completely editable. I can set it to change "Eric" to "Greek God With A Huge Penis" if I want to. Although that would be a lie.
The options for e-mail clients and calendar clients are much broader for Android. At least they used to be a few years ago. I'm not sure if that's changed.
How about using my phone as a simple USB drive? I plug it in, via simple USB, and it shows up as a drive. SO much easier than iTunes, IMO.
Then there are widgets. Widgets make smartphone life easier. Iphones don't allow widgets.
How about the replaceable battery? As I said in a previous post, I have a spare battery at home on a dedicated charger. If my battery poops out, it takes all of 30 seconds to swap it out for a full charge. I throw the dead one on the charger, and in a few hours that one is at 100% as well.
Let's talk about removable storage. My phone gladly accepts MicroSD cards. They show up immediately in the File Manager. Simple, and amazingly absent in iDevices.
I know Flash has gone the way of the dino, but many sites still rely on it. Works just dandy on my phone. Not so much on an iPhone.
In the more aesthetic region the biggest one is the custom launcher. A launcher is basically a "skin". it's what you see of the GUI. I can use one of multiple launchers available, and tweak it however I see fit. I can change icons for individual apps, I can rename 'em, or remove the text as a whole.
Look up Tasker for Android. It's an incredible app, and it almost wholly automates your phone, based on your calendar, your clock, hell, even your GPS location. it does incredible things. iPhone (as far as I know) has nothing even remotely similar.
These are just the first things I was able to think of. Gimmie a few and I'll think of more. I may not be 100% accurate, because I haven't owned an iPhone since my 3GS, so if I'm wrong on some counts, I apologize.