I don't know if the CS-1 is the squishiest, but it is an optical compressor and pretty brutal at what it does. People either love or hate 'em. I've got a couple of them, don't mind them, use them occasionally.
the squishiest compressor I have is the Guyatone ST-2. It is suprisingly good for the money and has a blend switch where you can blend in your dry signal, like a Barber Tone Press.
CS-3s are pretty squishy, but add in a bit of grainy gain at higher levels, like the DOD Milkbox and the MXR super comp - for a Chuck Berry type sound - nothing wrong with that, either.
My favourite compressors are the Boss CS-2 and the old DOD 280s/FX80s. The DODs are not 'sustainers' just compressors and are pretty effective.
These cheapies cover most of the ground for me. Of the 'boutiques', I think the T-Rex Nova is the only one that adds something that you can't get from the cheapies, that is, transparency. You can raffle the rest of the boutiques I reckon - the Guyatone (the cheapest of the lot) beats them all!