Go for it. Really. X100 cured my G.A.S and I'm not even considering the XPro1. The X100 even inspired me to write my first gear review for the website I bought the camera from (I'm way too lazy otherwise).
After several long months of browsing forums and looking for the perfect travel/daily camera, I finally went and bought the X100. I'm a strictly hobbyist photographer, mostly interested in shooting people, streets and buildings. I have previously (and currently) owned the Sony DSC R1 (an APSC sensor, DSLR lookalike, with a 24 - 120mm Carl Zeiss lens, a gorgeous camera but since it was as bulky as a DSLR, I found myself carrying it less and less) and a Panasonic LX5 (which the reviews raved about, 1/6.3" CCD sensor, 24 - 90mm lens, small enough to fit in a jacket pocket, but really bad in-camera JPEG processing which resulted in unusable JPEG images forcing one to shoot RAW/BW most of the time). I have used a number of cameras in the past for varying lengths of time, including DSLRs like the Canon EOS 5D, 7D, Rebel Txi, the Nikon D700, D90, etc, but have never bought any DSLRs because I was pretty sure I wouldn't have carried them out of the house. I guess I don't love photography enough to carry around several kilos of gear, lenses, tripod, etc! That's my meager photographic background, now onto the X100...
Let's talk about the bad stuff first - Be warned! The X100 is a different photographic beast since you can't zoom to compose images. You can't afford to be lazy with this camera. Composing images that with other cameras was just a flick of a button or a twist of the lens, is now an activity that reminds you to enroll for gym class. This camera has terrible battery life and barely gets you through a day of shooting (Fuji says 300 pictures on full charge, but it's more like 250. Buy several batteries, if you're an active shooter). The camera menu is a bit messy, but not as bad as the internets are making it out to be. Troll the nets to find out settings that suit your style of shooting, and stick with it so you don't have to fiddle with the menu systems often. The start-up time is a bit laggy, you can't just turn on the camera and shoot immediately, it takes a few seconds (3-4 seconds) but the start-up time improves exponentially if you format the card in-camera and use a Class 10 SD card. Using the Optical Viewfinder can produce parallax when close to the subject. There have also been lots of complaints about the slow AutoFocus in low light for this camera. It's no better or worse than my Panasonic LX5, just shoot in AF Continous mode and it's fine. Not such a big deal for me. Hmm... those are about all the negatives there are to this camera.
Now onto the good stuff and man are they good - Image quality! Image quality! Image quality! To me this is all that matters and no camera in this size currently produces the kind or results that this camera can produce. Period. If you want similar or better image quality you have to graduate to the Leicas (M9, M9P etc) and to me at 10,000$ and above, for a body and 35mm Summicron lens, this is not even a consideration. The Leica X1 comes close, but this camera beats it by a narrow margin IMO (though I like the Leica JPG engine which renders pictures with a pleasant red overtone, making it warmer than the FUJI, the X1 is more expensive by 800$). The X100 lets you shoot very very usable JPEGs without having to use RAW all the time, and the JPEGs have enough headroom to work with in post. The Straight-out-of-camera JPEGs are... how do I describe it... very film like. Sharp and soft at the same time.
The build quality of this camera is amazing, and Fuji have really put in a lot of time and effort into getting this right. The camera feels like a serious photographic tool, and lends confidence while shooting. The top and bottom parts are dye-cast magnesium alloy which house the controls for shutter speed, exposure compensation and the trigger. The lens has the aperture control, like any proper camera should, and once you know your way around the camera you will rarely look away from the viewfinder while composing a shot.
The hybrid viewfinder is a work of art and magic. Being able to switch between a large bright optical viewfinder like a DSLR camera and then at the flick of a switch have an 1.4 million dot electronic view of your scene is fantastic. To me that's worth the price of the camera itself. Parallax does show up when shooting close with the optical view finder, but Fuji projects a reworked frameline which shows how the image will be finally composed so one get used to recomposing pretty quickly. While shooting focus critical shots in low light, just switch to the EVF and you're good.
The metering and Auto White Balance in the camera is the best I've seen in any camera till date. The average metering works best IMO. Or while shooting portraits, turn to spot metering, point at the cheek of the subject (which is usually blown out) and click. The ISO performance of this camera is outstanding! DXOMark rates the ISO performance on this camera higher than the Nikon D3s till ISO 3200. The low light jpgs straight out of camera at 3200 are actually usable especially for FaceBook size images, though I would frequently restrict the ISO to 1600.
I'd like to end by saying that the most important factor to me, since buying this camera, is that it makes me want to get out there and take more pictures. And that to me is the best 'feature' of this camera. Good luck!
But I can say that with all that I have shot I still am always drawn back to my X100 shots. They are also some of the most faved of mine on Flickr....though the GF1 holds her own very nicely.
