I've had the a100 for about 5 months now and think it's a great cam. It's lightning fast in allot of respects. 

My only complaint (and this is a well documented issue with the a100) is high ISO and extended exposure shots produce noise. In fact just a week ago, I was shooting at night with some 7min exposures and they all came out so noisy they are useless. High ISO like 800 and 1600 also produce allot of noise. Though it starts around 400, it's easily removed with 3rd party programs like noise ninja (which I use).

Aside from the noisy ISO issue, as long as you don't plan on shooting quality images in low light (without a flash) or do looong exposures (seems 2-3 minutes and the noise isnt bad at all) then it's an awesome DSLR camera.

I'm waiting for the new bodies to come out from sony in june/july but will always have and use my a100.

Btw i got the 18-70kit version and I have a flickr gallery of all a100 shots here