For most of us the answer to your question is probably not. As a matter of fact, for normal size photos, I see no improvement of the Nikon d800 over my Sony a580. However, when you get into the fine scale of things, there is quite a difference but mine is more than adequate for what I do.

I do like the fact that the a99 is updated from the a900. You do realize that the sensor being full frame, is different than the a77 even though they have basically the same megapixel count. I also like the fact that they held it down to 24mp vs. the d800's 36mp which I understand is the same sensor. I may be wrong here. But with 24mp on that size sensor, they are not trying to cram as much information on to the sensor as would they have with 36 mp. This should result in better color representation at the least.

A good example of this is with the a500 12mp camera vs. the a550 14mp camera. They both have the exact same sensor but they found that the picture quality on the a500 was much better than the a550 because just by adding a little more to the sensor degraded the picture quality just enough to be noticeable. Just goes to prove once again that less is sometimes more.

Sony now has it listed on their website complete with specifications. It is also geared better for movie making along with the expensive accessories that go along with video.

But if Sony has done their homework correctly like they usually do, the a99 ought to be dynamite. At that price it better be.

I agree with you for the most part. I own the Nikon D800 (which I believe you are right “same sensor”) however in order to cram that many megapixels on the camera they had to improve the software for processing the image and that makes the D800 slow, however it does a good job of noise reduction at high ISO. Both the D800 and the A99 are boasting 14 bit channels which puts it in a class with medium format cameras for color representation. The only advantage of the large megapixels on the D800 is cropping or extreme poster size blowups.
I realize that the sensor is full frame on the A99 versus the APS-C A77; however the remaining features are more akin to the A77 which was their top of the line SLT. From my standpoint I wish the A99 was a DSLR rather than SLT, every time I am in the field changing lens on the A77 in windy weather I cringe just thinking that dust will get on the translucent component and scratch the coating. Don’t get me wrong I like my A77 just treat it with more kid gloves than my other cameras.

Buy Minolta AF lenses (their high end at that) and you will save a ton of money. They are all full frame if they came off of a 35mm camera. They are sharp, crisp and some are real fast. I paid $30.00 for a used 28mm F2.8 wide angle prime for my a580 for example.. It is excellent. I wish I had the a99 because the a580 can not totally use the wide angle capability. I have all sorts of great Minolta lenses that I bought on the cheap. I guess I have something to save up for.for.

True, but a "G" lens in the old 35mm Minolta line still costs $1,000 on eBay. The "G" lens on the Minolta were the top lens in their day.