First, my disclaimer: software author has my positive comments on his website, with my permission. I tried this, paid for it, use it. No other connection with author.

I am really happy with Sonicmood. I have an oldish iMac that is running several things at once, but can detect no slowdown from SonicMood, or if any, less than I get with my favorite internet classical music station running. Real music sometimes captivates my attention, while SonicMood is just good background stuff for me.

I find the sounds simultaneously soothing and invigorating, seem to make it easier for me to focus on tasks or put up with the boredom of sorting through long columns of figures or whatever. I also have my "relaxation area" near my iMac and find these very zen-chime like.

The only delay I've found is when I want to quickly turn off the sound--as when I'm being invited to an iChat session--it seems to take a couple of seconds for the "pause" button to go from gray to useable.

I warmly recommend a download of this, as it has a one-month free trial. I found it quite worth the price.

Oh, my credentials, for what they're worth: in my "other" life, I'm a psychiatrist working in some pretty stressful settings. I really value being able to calm down while reading my email.

And I've already had a couple of friends who commented how nice it was to be near my computer with SM playing--and then I was able to gloat that it was just too bad they were running Windoze instead of a Mac...