Disabling Spotlight will disable the search at all. So when spotlight is disabled, and you do s simple search inside Finder (for example to search a file on an AFP sharepoint), you will get no results.
You will lose search functionality. The Icon in the top right corner will still be there, but you can type what ever you want: you will find nothing. (There was a hint to get rid of the icon somewhere, but I don't remember where...)
The Photoshop bug while saving is going away, however, we have often a EOF-Error.
I ordered a maintenance now to bring my server on 10.4 and then we're going with PHD.