I have operated both Gulfstreams and Globals and I must say it is the luck of the draw.
Brand new Gulfstreams could be temperamental coming out of the completion centre (ask the guys at Long Beach !) but tend to settle down well during most of their working lives.
The Globals tend to be painful with frequent avionics glitches. Also, their cabin trim is cause for many owner complaints. I'm no Bombardier basher - maybe it's just my bad luck.
7Xs are not spared either. I heard of both gems and dogs.