I have the Swisstech and the Squirt P4. I used to have a Sebertech. Know next to nothing about the Clutch.
I had problems with the handles of the Sebertech opening in my pocket. Next, the SwissTech. Much less trouble with the handles opening in my pocket. Next, the Squirt. Handles much more comfortable and do not come open accidentally. I like the longer nose pliers on the Squirt better, Leatherman pliers are always nice. It is prettier and the tiny file is kind of nice. As a stand alone multitool it is the winner, but
My recommendation: The SwissTech. Much less costly then the Squirt. It is more compact and more scratch resistant than the Squirt, making it great for keychain and pocket use. It has no knife blade and I have taken it through airport security with my keys. Get the one without extra tools and get a small SAK like the Soldier, Cadet, Bantam, etc. to go with it.