If you climb multi pitch with singles i bet the new Gri Gri would be a good unit. $$$$ Pricy though.
I like the ergonomics of the Cinch better. I've never used a gri gri for lead belaying. the weight difference is minimal. plus since i already have a Cinch it is simple.
I love my Cinch for a few reasons.
1) Zero resistance when taking in slack while direct belaying off the anchor. There is no better way to pull in 600 feet of 10mm on the slabs for 7 pitches guiding.
2) Instant lock when loaded... while the brake hand still needs to be on the rope this cam locks up much quicker than a Gri-Gri, which is preferred when belaying a second or TR'ing IMO, but makes this less ideal for belaying a leader which I never do with it.
3) You can install this on a fully loaded rope, adding to it's functionality in self rescue as it can function as a smooth ascender in that application.
4) Works down to 9.4mm (unlike old Gri-Gri 9.7)
1) Does not rap half as smoothly as the Gri-Gri, especially the new one.
2) Not great for belaying a leader.
3) New Gri-Gri works down to 8.9mm.