As an iPhone 3G user, a jailbroken iPhone - I did that to my iPhone 2G (1st Gen) but not my current 3G - is more featured laden than the original carrier based only iPhone.

And with my experience with the N810... even that's (jailbroken iPhone) not up to the same level of "what you can do" with Maemo. Therefore, if you're not too married to the iPhone 3GS - I have some Unity3D based projects that will keep me on the iPhone in at least as a dev for the next year, but some friends of mine have a TON of iTunes music they've purchased that was before the DRM-free days - I'd say switch.

Especially since you'd like to be able to manipulate the phone. I find jailbroken iPhones to be a honest step in the right direction in terms of not feeling like you're in some ultra-confined box; however it's still missing something. Namely... the next upgrade, it will invariably break that independence since Apple wants way too much damn control over your purchased phone... whereas the N900 seems to be that wide open road that most people with an ounce or two of technical savvy will love.

If the N900 ends up being close to what it's hyped to be - and offers a video communication and/or experience (for sharing) - then I'll be switching myself from the iPhone.

Oh... and the lack of true multi-tasking truly is a pain in the butt.