Let me just start by saying I know nothing about Bombardier products. At all..
Had an interesting conversation with a G650 jockey the other day, and he said that contrary to rumors, the airplane works just fine, and does what the book says, same as previous Gulfstreams. No AOGs in 1 year of ops, which is a lot more than i can say for our 7x, and even for our fairly new 550..
The g650's bad rep stems only from its dismal cabin management system, and the not-so-smart decision to automate and electrify everything in the back, down to the fresh-air gaspers (!)..
So providing they sort their cabin out in the next couple years, the G650 should be the top performer on the market for a while to come, and will have it's dispatch reliability above 99% before the first Global 7000 even leaves the production line..