I did alright with mine. I figure a modern one would have modern hardware in it. People forget how dire the performance on the first couple of iPhone generations was, too. The N900's contemporary was the iPhone 3GS, I think, which was an objectively terrible device in every metric except sales.
Oh, and the N900's inbuilt phone dialer was also kind of ass. But I found its performance more than acceptable, and it could run full fat Firefox including the Flash plugin, which was still a big deal at the time, whereas its competitors could barely render a web page.