If you're shorter or don't have particularly long legs, the restraints are annoying but tolerable. If you're tall or have long legs, they suck and will most likely affect your enjoyment of the ride to some degree.
I backed out of Eyehategod in Boston last year when I had tickets because some stuff happened at the last minute that would have made it extremely difficult to go and I also had to back out of Revocation there back in April because of car issues (made up for the latter by catching them in Hartford a few days later; basically got out of work at like 8:30pm and tore off down 91 to get there right as they were finishing their soundcheck). Definitely not missing Hate Eternal on the 27th, though; it'll be worth the Brighton Music Hall's godawful parking situation.