I haven't yet owned the SP-A900B, But I did have the Samsung SP-A800B (which is supposedly the same lens minus a few tweaks that were made for the SP-A900B ). I don't know about the "sharpest" looking picture but there was this clarity to the image that I've never seen before. The whole image had this effortless look to it that just screamed "I don't need a darblet"
So yes, the optics in the Samsung models are the beset I've yet seen, followed by the Marantz VP11S1/2 and 15S1, Sharp XV-Z20000, and then the Planar PD8150. All of them look amazingly sharp. That is one thing I love about DLP projectors of this magnitude. The image looks so consistent because the pixels seem to flow into each other (ie lack of a pixel grid) while also resolving a lot more detail for your eyes to see. This extra sharpness can only really be appreciated if you're sitting at the recommended length away from the screen or closer. The JVC DLA-X3 I had looked very sharp for a three chip projector and with a lens that I'm sure doesn't meet the quality of the one's I've mentioned and yet if you sit far enough from the screen (maybe an extra 50% farther) DLP loses it's edge because your eyes simply can't tell a difference.
So, to the OP, your seating distance to the screen does matter. If you plan on sitting far enough back I wouldn't bother looking for "the sharpest" DLP model and go with another DLP model that has a feature you like. The reason I wasn't sure if the Samsung was the "sharpest looking" is because with real world content and me comparing off memory what others may have looked sharper is very hard. When I get a new projector I typically watch the same 10-12 clips on every projector that I get. This makes it easier for me to compare them because I've seen the clips so many times. When you've seen so many uber sharp DLPs it's hard to tell which one looks sharper with real content. I tend to tell myself that if it can resolve a single pixel better that it must look sharper with actual content. In this case, the Samsung models are the best. I'd only worry about getting the sharpest looking DLP mode if you plan on sitting particularly close. To be honest, every single .95" DLP DMD projector I've encountered has looked remarkably sharper than any .65" DLP, 3LCD, or LCOS projector I've had. You can't make a bad choice with the larger DLP chip.Edited by Seegs108 - 5/27/13 at 11:27am