Well, if I had an iPhone, I wouldn't jailbreak it. It works like a dream right out of the box. I need root because I don't feel the stock HTC Sense Android experience is satisfactory, given how much better it can run.
I've had my rooted Evo for three months now and I'm on my fourth ROM, none of which have I found entirely satisfactory. The ROMs I've used thus far are FreshEVO (don't like Sense 2), Evervolve R3charge (Sense 3 is kinda choppy, not enough customization), CM7 (no GPS fix I could find, but I LOVED it on my Hero), and now Xplod (again, no GPS and still in development, so some important features are still wonky).
I was an Apple laptop-only person for almost ten years until I couldn't afford two summers ago and we've got an iPad 2, so I'm familiar with both Android and iOS pretty intimately. There's tons I love about Android, and maybe I wouldn't enjoy an iPhone once I had it, but I'm tired of the ins and outs of rooting, ROMs, etc. There's some pleasure in it, but only when you finally find the right one, which I haven't yet.