Id buy another given the right price. I see people walking around using phones sometimes almost a decade old, not smartphones of course. When asked why they still have/use the hardware/software, im usually told they like it, and it works very well for their needs.

I'm going to be that guy walking around with a n900 until something comes along that fits the bill to replace a piece of hardware im very accustomed/comfortable with.

I think the main reason n900's still have a market (used, new, stock clearance by retailers), is the open source aspect of it. Really nothing else with hardware like the n900, and a community/software/os backing exists to my knowledge.

One big thing for me personally, is its build quality and durability. I'd wager i've dropped my n900 over 50 times in its lifetime, on concrete, while biking on and off pavement, stone/hardwood flooring, you name it. I abuse it, and have had no hardware issues save a replacement for the headphone jack.

Granted an otterbox case, and invisible shield screen protector helped alot, but i diddn't always have that, and all other phones i've had wouldn't stand up to the abuse i put my n900 through.