I had both. Bought the Hobbs from ex ITCC champ Dan Kraus for $700 (He'd won it in a comp), then sold it back to him years later when he started Champion Tree Care--for the same $.. so I used it fo free! The GRCS is very capable of handling the same large loads and has the advantage of being able to employ rapid slack removal during negative rigging, to reduce the free fall distance. I've neg rigged up to perhaps 2500 lb! Yikes.
My GRCS was #343.... cost me $1200 as an arb bud and I shared it.... he ran a slightly larger co, then moved to Bartlett and Arborwell, taking it along.. But I always used it more as I love the tech rigging challenges. Got the longer arborist capstan which allowed for a full 5 wraps with larger lines! Sold it back, as I'm retired..but stand by for pics and vids from a recent job. Even you will be impressed!
By the way, Dan, about to turn 58, is still competing... he came 2nd last weekend, and twice in the top three at a couple NAOM events. HE's amazing. I'm 75, fat lazy and old... but have worked 9 days this year... climbed a few trees but had my buds do the big firs on the log job---we got 6100' on one log truck!.. tall forest grade logs but on a large residential lot. Heck, over 10 years ago, we removed some 160' cottonwoods at another place... that were under 40" dbh!!
I will be sure to do a bit more work, at least into October..as that will mean I've officially worked in the trees for half a danged century!! Actually, I logged in Ak off a floating quarters for three weeks back in 1972... but was a total greenhorn who had started a job for a landscaper a bit before that, and went back to it after getting a slight injury in Ak, 3.5 years later, I started at Washington Tree Seervice--was fired 1.5 years later for screaming at the estimator for 5 crews "why are we topping these trees----in half?!!" Found a slightly better position, still did some tree topping (small tops, shaped the tops and did some thinning) Then, stated Barnett Tree Care in '85, joined the ISA in '89 and started learning better and proper tree care.