Ight, on the issued OCP (multicam) uniforms...
They aren't ACU's, they're FRACU's. 'Fire Retardant' chemical coated/soaked. Or so we're told. It's actually a bug repelant, but they only remain effective FR for the first eleven washes or something.
The material doesn't seem the same because of how fast it wears and the way it rips, always feels grungy/greasy/dirty, very cold on cold mornings, and they seem to fit differently. The last part may or may not be true. Many guys that have never ripped out ACU's were ripping the croches out liike crazy. I think the croch is cut lower. That, or the material grabs instead of slides on skin, so instead of riding up when moving legs, the pants stay and rip.
The best source for any USGI clothing and equipment is going to be ebay. If you issue it to soldiers/troopers/marines/airmen/sailors/etc, it'll end up on ebay en masse. Brand new, lightly used, or used to shit for those of us that might want to buy something there for turn in (keeping our original item).
I'd suggest getting something better than OCP FRACU's if you want something that feels and wears nicely. As for buttons/velcro on the cargo pockets; big mistake, get the buttons. Velcro isn't only noisy, but the cargo pockets velcro usually wears our and your pockets hang open. We were happy there were buttons on the cargo pockets of SOME of the FRACUs we were issued.
There's a lot of the MOLLE GEN III stuff on ebay. That is GREAT stuff, for the price.