ML should be quicker and snapier. The only way to tell for sure would be to do a clean install, after re-formatting your HDD. You don't say whether you tested that while it was still clean or migrated first.
The reason I say a clean install, is because it may be your hard disk, even if Disk Utility says it's OK.
For now, see what happens in a fresh user account, or log in as Guest. Is it still slow?
Apple support article covering what macjack suggested.
If the problem is still there, try booting into the Safe Mode. Shut down the computer and then power it back up. Immediately after hearing the startup chime, hold down the shift key and continue to hold it until the gray Apple icon and a progress bar appear. The boot up is significantly slower than normal. This will reset some caches, forces a directory check, and disables all startup and login items, among other things. If the system operates normally, there may be 3rd party applications which are causing a problem. Try deleting/disabling the third party applications after a restart. For each disable/delete, you will need to restart if you don't do them all at once.
Articles covering improving performance:
Thanx for the quick response guys!
I signed in as a guest and although i couldn't really test the speed using all my regular apps, it did seem a lot faster. I think a clean install is worth a try. However, do you recommend not using Time Machine to migrate my files back at all? (not even keychain and mail)?
You guys are right.
So I looked into login screen under users, but there was only Canon IJ Networks and Itunes Helper in there.
I shut both of them off.
I also ran Safe mode. While in Safe mode the graphics were staggering a bit, dropping frames when opening a folder from the dock or going to mission control.
I Rebooted again and now things seem to be working nomally. But I have to test over a longer period to be shure. So I'll keep you posted on my experiences.