Not really. Android can do the same thing the iPhone does: Suspend background tasks when you launch new ones, and allow background tasks limited time slices to handle real-time events, like hardware requests, dbus messages, pushs, etc. It's not true multi-tasking. As far as I've seen the N900 is the only one that does that. Admittedly, that's part of why the battery life is longer on those devices, and why they sometimes "feel" less "sluggish" than the N900 can at times.

As for this thread...
I had an N6230 for 5 years because it did all the things I needed it to do, and had a very usable J2ME VM. Before that I had a semi-smart Motorola device for 3 years, similar reasons. The devices were very open for the time (full obex support, well documented Java APIs, etc), and did what I needed them to. I'm willing to bet the N900 will be with me for a few year, at least until there's something I absolutely "need" that the N900 can't adapt to do (probably hardware wise).

As of right now, it's stable and does everything I need and want to do on it (with a rare occasional glitch, but everything does that.) It's a decent phone, a great netbook, and a top-notch organizer/communicator. I've got tons of bells and whistles added, and it just does everything I need. My biggest fear right now is that it breaks (usb, drops/screen cracks, etc), and I won't be able to get my hands on another one.

I still look at new phones that come out, and there are a couple that could probably do most or all of what I want (when rooted). But the N900 is still in my pocket for three simple reasons:

• The hardware is top notch (Nokia's just good at that)
• The software is mature, stable, and relatively open/malleable.
• The community is active, responsive, and knowledge rich.

If I find another device with stable hardware, mature/open software that meets my usage patterns, and an active stable development community, it may be a decent replacement for the N900. But I've yet to see that in another device, and I've been looking. Once I find such a competitor, I'll have to then consider if it's worth the time and money to move to the newer shiny thing.