I've had the Samsung Epix i907 Windows Mobile smartphone (AT&T) for
about a week now, and spent two days or so getting extra-cozy with it
on a trip to Dallas late last week.  While it's no secret that I'm not
a big fan of Windows Mobile in general, I also won't make a secret that
I've been really pleased with Epix itself.  Early "reviews" were hard
on Epix for having a thick profile and what some called a superfluous
feature in an optical mouse where the D-Pad would normally go.  Me, I
actually didn't mind the phone's size (it's largely offset by its light
weight) and found the combination of touchscreen, optical mouse, and
full QWERTY board to be a victorious triumverate.

First off, Epix hasn't crashed on me even once.  Can't say that about some of the WinMo devices I've tried in the past.  Reminds me of when I first got a Motorola Q9 to review some time back and took it on a trip with me.  I distinctly remember almost losing my marbles in a United Airlines terminal somewhere when our flight was twice-delayed and I tried to take solace in reading some sports news on the Q9.  Crash, crash, crash and I nearly broke out in sobs.

Next,
battery life is much improved over the notoriously short-on-stamina
Blackjack and Blackjack II, which Epix essentially replaces.  Thin may
be in, but thick adds room for a beefier battery, which means you can
rock the 3G a little bit longer than your iPhone-toting friends.

Beyond that, I really like the use of the optical
mouse.  It's not much different than the trackball that RIM and HTC
have recently employed on the Curve/Pearl/Flip and G1, respectively,
but it might actually be easier to use than a trackball.  The optical
pad can be set to full-on mouse mode or to a "sweep and pan" mode
depending on the user's preferences.  I found it really handy when
browsing the Web and trying to click on those tiny little hotlinks that
touchscreen phones are notoriously bad at dealing with.  Several times
I honestly forgot that Epix also had a full touchscreen, and got a kick
out of remembering ... and then mashing every vritual button in sight
with my thumb.

Speaking of browsing, I also installed a Beta of the
Skyfire browser on Epix and it worked quite well.  I wasn't quite able
to "enjoy" streaming Flash videos from Hulu or YouTube (as I'd seen
advertised on some forum or another), but Flash does work on Skyfire -
at least in theory.  Complex pages rendered very quickly via Skyfire on
Epix, and I'm looking forward to playing around with the browser a
little more.

I still find Windows Mobile to be a clunky, annoying
OS, and Samsung didn't put TouchWiz on Epix so none of the WM 6.1
experience is hidden from the user.  But the actual hardware worked
very well for me - at least in initial, limited testing - and the fun
of using Epix itself overshadowed whatever personal bias I still harbor
towards WM.  3G data worked well in Dallas and Oakland, WiFi was
decently strong, and Samsung did a nice job with the camera and camera
UI, in particular.