I've been playing with my brand new Sidekick 3 for the last few hours, and I'm pretty impressed.
I owned an original Sidekick way back in 2003, but while it was a great Internet gadget, it was a pretty crappy phone. I ended up dumping it for a Nokia 6600. Sadly, my trusty Nokia has begun to show its age (and refuse calls), so I have once more laughed in the face of Danger and taken a bold leap into Sidekick land.
The Sidekick has gone through three hardware revisions and countless software upgrades since I last looked at one, and the end result is pretty slick. The Sidekick 3 is much smaller than the original, and even than the Sidekick 2. It's still just a tad large for a mobile phone, but at least it doesn't look like a brick anymore. It actually feels like a phone when I hold it up to my ear, which is pretty sweet, since talking on the original Sidekick was a little awkward.
Everything about the Sidekick 3 is slick. The new shell, the flip-out color LCD, the backlit qwerty keyboard, and especially the translucent trackball, which lights up in a variety of sexy colors when certain events occur (like incoming messages or phone calls). I'm also mightily pleased with the inclusion of a ringtone that sounds more like a normal telephone ring than any actual telephone I've heard in the last five years. It's such a convincingly normal ring that it's a little hard to believe it's coming out of this sexy, sexy gadget.
There are the usual downsides, of course. The built-in 1.3 megapixel camera takes horrid photos (although the photo application itself is really sweet). I still think it's ridiculous that you can't install unsigned third-party software unless you obtain a special developer key from Danger. The Sidekick has the best mobile OS on the market, an excellent user interface, and a great API, but any innovation is effectively stifled since users can only install commercial software distributed through official channels (and the official channels have no interest in distributing free and/or open source software).
Nevertheless, I'm pleased with my purchase. Now I'm just trying to think of a semi-useful application I can submit with my developer key request so Danger will let me install unsigned code on this thing. If anyone has any ideas, I'm all ears.