Don't be too quick on that sale trigger. If nothing else, put the proceeds aside so you can use it as a down payment when you come back. Been using an iPhone for about 4-6 months now and am ready to go back now that WM6.5 is out. Wish I could wait for 7, but I'm old and might die first. While the iPhone at first was pretty cool, good feel, responsive, nice UI, there are continually things I miss. First and foremost is multitasking. I don't mean writting a novel, answering e-mail and working the company budget in Excel while talking on the phone, I just mean cutting and pasting from one app to another without having to close the app and re-open the other to do so. The lack of multitasking in the iPhone is one of the reasons for it's stability. Hard to get confused if you only do one thing at a time.
You touched on the keyboard. For me it's not just the keyboard, which I find frustrating, but the lack of any other options. Even without the available hardware keyboards on WM devices if you so choose, you get a stylus driven one, third party finger friendly ones, handwriting recognition, both native and third party, bizzare ones like Fitaly, and even some reminiscent of Palm Graffiti if that tickles you. Have you noticed it takes a great deal of effort to shout in an e-mail on the iPhone? No Caps lock. At least I haven't discovered the 'intuitive' way there must be to do this. So I am stuck with up arrow H, up arrow E, up arrow L, up arrow P, change characters !, if I want some HELP!
Another thing I discovered this weekend. It is clear that the phone was designed in sunny California. You know you can't answer it with gloves on. It was 20 freakin degrees (Farenheit) with the wind blowing, and since there isn't an answer-the-phone hardware button, and the adorable little slider won't respond through gloves, I had to take my gloves off to answer my iPhone.
Another thing. WinMo will save you money in the long run. With the wide assortment of manufacturers and body styles in WinMo, third party accessories are not as prevalent. Why is that good? Well I'm not tempted to by that clock radio, TV, toaster, lazy boy recliner with the iPhone dock. With WinMo, if I get tired of the style of phone I have, I can get another without obsoleting the entire ecosystem of attachments I have been sucked into. (how's that for spinning lack of third party support into a positive

)
So, enjoy your iPhone, you will, but don't discount the possibility you will be back.
BTW, iPhones do lock up. On several occasions mine has just decided not to have the phone part work, while everything else did. Symptoms were, you couldn't call me, it just went to voice mail, and I couldn't make a call, I could dial, but nothing would happen. Turn phone all the way off, which is another intuative process, and turn it back on, and all was well. Think that minor inconvinience was remedied in the last update, but it does appear it was a feature of the update before it.