i think you need to see how much of a dog you will get out of it at the end, i know people who once their dogs cruicate goes they put them down.is it right or is it wrong
..?? i think it depends on the person and the dog to be honest and how much of a life they will have after it, if i thought the dog would suffer more than he has to and would not have much of a life then i think i would have to have a serious think about it, but thank god the op on mine went ok but whos to say when or if his other one goes, and it goes badly then things might be different in terms of the life he can lead, or if the one that has all ready been done goes tits up again 
as for the cost intotal its cost me £2,500 ish and im not a rich man think you need to have a think, shame you are not from this way as you could have gone down to exeter and seen the consultant i seen like a few others on here have he will tell you how it is like he did with me.or maybe give him a ring.. 
But once diagnosed my vet put me in touch with Leahurst veterinary school as the only place he could find local to me..cost £2400 per leg. Dog was uninsured so I looked around...found a specialist in this area and strangely enough he worked at a practice only 10 miles away ...cost after explaining no insurance £800 per leg. He was very good to explaining everything in layman's terms and giving an honest prognosis before and after .