Yes I have used it, had no problems with it and it has speeded up scripts a goodly amount.
Running the same script (about 10 mysql queries and a fair bit of perl processing) I get the following times for page generation.

speedy : 0.06 seconds
normal : 0.20 seconds

Bear in mind that the first time you run the script under speedy it will run a bit slower (about 0.22 for me) but subsequent runs will be much faster as shown above.

Hope this helps.