I'm not keen on the Kyser or spring loaded Dunlop as the springs are rather stiff and allow no adjustment of pressure on the strings, sometimes putting the tuning out. I do, however, use the latter if accompanying Irish music in DADGAD for quick key changes. I haven't seen or tried the G7 yet.

My favourites are the Victor capo (now distributed by Dunlop) which I use on my resonator and jazz guitars and the Bird of Paradise capo which I use on my Lakewood (primarily fingerstyle) which has a custom wide fretboard. I also like the Paige design and use one of these on my octave mandolin. All the above are precisely adjustable to give any desired string pressure. The BoP also works very well on my classical.

Hope this is of some use.

Peace

moo