I have noticed no slowdown or major bug (yet).
But KUDOS! A bug which has been bugging me for some time has been fixed. Previously when I deleted images, especially a large number, I got an error which popped up a dialog which had to be dismissed (don't remember the wording). It took some time for this dialog to appear and the program was unresponsive until it was dismissed. I delete a large number of images for for each shoot because I am taking sunrises using the HDR panorama feature. Each set of images may be from 25 to 60. There are many sets of images because the sky changes quite rapidly during sunrise and to get the optimum image you must shoot through the sunrise, taking a set of images every couple of minutes. So it is expose a lot, cull, and destroy. I might shoot 600-700 images and keep 80-100.
As long as I am handing out kudos, one must go to Photoshop. This major for me. The behavior of the Align option for the Clone Stamp has been fixed. Well not really because you will no longer find Align as an option. It has been replaced by a new option that has no name, just an icon of two squares on top offset by two rectangles on the bottom. The hint for this icon is "Use same offset for each stroke". So it does the same as Align when activated.
The problem with Align was that you could not control it. It had a mind of its own. When you selected a target it would sometimes trigger the Align option and sometimes not. Or if you checked and Align was not selected and you proceeded to work and suddenly things got all screwed up, it was because Align was mysteriously activated.
Why is this important to me? Because as I said I do many HDR's and one big problem with them is that are sections of the image that do not get the same intensity as the surrounding area. For example a tree with lots of sky areas showing through the leaves. These areas are often much brighter than the surrounding sky like Christmas tree lights. Another is halos at the horizon. To get rid of these artifacts I use a technique with a blank layer set to darken and the Clone Stamp set to darken at a low opacity. You must know where the target area is so that you can match it with the light area. If you cannot control the target the technique falls apart. You select a target that approximates what the light area should be and brush in until it looks good. It is the only way I know that fixes these artifacts.
So there is hope. These two things were long standing problems. Adobe is finally getting around to fixing the small, niggling things. Things that don't get much press but in practice annoy the hell out of you.