I'd take the Sony VPL-HW50ES over either of those models. I've owned the InFocus IN83 and it isn't really all that nice in comparison. Black level is okay as long as you're closing the iris down close to all the way. Sharpness for a .95" DLP DMD just isn't there in comparison to other similarly priced .95" DLP DMD projectors that were out at the time. Another issue is that there is no lens shift and there is a default offset of 36% off axis, so it has to be mounted perfectly for it work. I also found an odd alaising issue with the IN81, IN82, IN83 line of projectors. Its has to do with an software oversharpening of the picture that can't be completely eliminated. It resulted in visible ( easily noticeable) aliasing with any sort of vertical and/or horizontal lines in the picture. An example would be the beginning shot of The Dark Knight. As the camera moves closer to the building all the vertical edges of the building and windows would alias and product a rather annoying and strong artifact.
The SP8602 has a clunky dynamic iris and is the only way for it to achieve decent contrast. So you'd have to live with pumping issues with that particular model. It also uses the smaller DMD and retails for less. You can expect sharpness to be avergae for it's price point. I've actually found that the newer JVC models are just as sharp looking as all the .65" DLP DMD projectors I've seen, which is a shame because that used to be something DLP has in it's back pocket. Though, they still can't match most .95" DMD DLP projector for sharpness. The IN83 is still a small step up over the JVC models, but not as much as basically the rest of the larger DMD DLP models.