6.1 megapixel SuperCCD makes files as large as 4,256 x 2848 pixels
Beautiful color, particularly good with skin tones
ISO from 100 to 1600
Excellent low light performance
Accepts most Nikon F mount lenses
Fuji's original S1 Pro did well partly due to its beautiful color rendering, and partly due to a price that was thousands of dollars less than other D-SLRs at the time of its introduction. A lot of people (myself included) have questioned whether Fuji could stay in the game with Canon and Nikon's competing models actually selling for a bit less than the S2. I confess that I approached the camera with more than a little skepticism, expecting it to come up short after the wonderful experience I'd had with the Nikon D100 just before it. I was thus somewhat surprised by how much I ended up liking the S2. Its color is indeed every bit as accurate and (more to the point) as pleasing as the S1 before it, and I was genuinely amazed by its resolution and how delicately it rendered fine detail. I didn't like its body style quite as much as the D100's, but the differences are relatively slight. I really liked its user interface design, with the small rear-panel data readout and "soft buttons" below it, but this is very much a personal preference that others may not share.
What's clear though, is that Fuji has crafted a very strong entry in the 6 megapixel D-SLR category, and are very much still in the game. Fuji had a strong market for the S1 among commercial portrait and wedding shooters, thanks to the excellent handling of skin tones. The S2 will likely continue to lead that market, but will find many other happy homes as well. Kudos to Fuji for another well-executed entry in the D-SLR race!
The S2 is one of those cameras that is the oldest in it's generation, but still a very worthy contender.
The 12 MP sensor that is composed of 6 normal MP and 6 extra MP to expand the DR, well, it just works. You don't get the resolution that a true 12 MP camera like the 5D would deliever, but then again the 5D is $2500 and the S2 Pro is approaching $500 in good condition.
Especially if you're an event photographer, namely weddings and portraits, then you owe it to yourself to check out the Fuji system. If you shoot JPG, then you owe it to yourself to check out the Fuji system AND I can almost guarantee that you'll want to own one. They just WORK very well, and those who try Fuji DSLR's always have something good to say about them.
One problem is that Fuji is debuting it's newest DSLR, the S5 PRo, at a price that most people don't want to pay for "only" a 6+6 MP sensor. Personally I'm going to because I don't like the ergonomics of the S2 or the S3, but for most people, the debut of the S5 Pro is going to be a great opportunity to purchase a used S2 or S3. Like I said the S2 is approaching $500 these days, and the S3 is starting to drop below $1000, both for good / mint condition bodies. At these prices, you just can't overlook them.