I love my android phone! The spellcheck through the swype text entry system is a lot better than the iPhone's autocorrect.
I don't see much difference between them - the big pull for either is the apps, and most apps are available for both, or equivalent ones anyway, so there isn't much to choose from.
Sometimes iphone apps come out first (e.g. the mumsnet app) but OTOH, android is completely open source, you can opt to download any apps you like from anywhere on the web, whereas with apple you can only go through their app store.
Android most definitely, otherwise you're tied to Apple and iTunes completely, whereas androids can be treated like an external hard drive on your computer, making it easier to just drag and drop files rather than having to do a full sync.
I've had to send 2 HTC Desires back and both had the same problems, friend has 1 and has had the same problems as well, another friend has the Wildfire and also has the same bloody problems.
Vodafone for my troubles decided to give me a hefty amount off a new phone because I pay them a fair amount on my bills, so I bought a Galaxy tab. So far it is brilliant, but not exactly compact and really if you want to use it for calls you need a bluetooth headset. At the same time I also got the Iphone4 as an upgrade to a laptop contract, I personally found it a bit boring and gave it to my DP but he loves it.
Mine is a samsung, the galaxy apollo, though it's a low-range smartphone, it can run most apps I've tried. The only thing it struggles with is 3d games, but there are plenty of other games for it. DP has the top-range one, the galaxy S2, and mine can do most of what his can - his is just a bit faster and the screen is a lot brighter! The camera is better on his though and it has a few extra features such as HD video recording, and an extra camera on the front so you can do video calling/skype etc. I'd definitely look at a mid-range samsung as well, they are very well made. The inbuilt alarm is fantastic as well, it has an option for smart alarm which means it wakes you up gently rather than a sudden thing. (Though you can download an app to do this on the iphone I believe)
Also another android vs iphone thing - I'm not sure if this happens on iphone, but if you install an app for e.g. facebook or skype on your android phone, it has the ability to add options to the menus, so for example when you are viewing your pictures in the gallery, it has an option there to publish to facebook if you have the facebook app installed. When you select a contact in your phone or highlight a phone number in e.g. a text message, it gives you the option to call that number using the in-built dialer, or via skype, just for example. You can also customise your home screen with pictures etc, and put shortcuts to your most used apps, contacts, webpages, etc, and add little widgets and things. I don't think the iphone even has a home screen, though you can change the picture on the screensaver.