The real test of excavators, is when you eventually get out to that 7500 to 8500 hours mark, and have to start replacing or rebuilding some components. Good maintenance, good operators, good materials will buy you some time, but unless you figure to trade or sell at that point, the Cat will get you maybe another 2-3000 hours over the others. Course, then you still have to do something with it, eh? I've had good luck generally with Komatsu PC650's and 400's, but the 650 was where I learned the 8500 hour rule of thumb. Kiewit and others have had real good luck with Hitachi machines, maybe one of the driest excavators on the market, hydraulically speaking.
Dealer service is usually going to be better and quicker with Cat. Parts availability will be better. Equipment follow-up is way better with Cat. Resale value is much better and demand for used Cat's is better.
I guess I'm used to being with bigger contractors whom get better deals on equipment, but the cost-spreads fellas are mentioning here seem kinda extreme, not that I haven't heard things like this before. But Cat can and usually will get down in the muck and get dirty with pricing if they really want to make a sale, no matter if the purchaser has only one machine or a thousand. The last outfit I was with was a medium size contractor, but didn't have a lot of yellow iron. Still, the boss would just skin our CAT salesman alive on price and warranty's. We did have the advantage of being able and willing to buy in another state if we wanted to, that sharpened up the competition some. Still, you gotta play hard to get no matter what size your outfit is.
Good luck!