First of all, as a lefty, I love the new tac-latch. Before guys start b****ing though, I understand why right-handed shooters hate it. If I had that long metal prong sticking into my gear, I'd be pretty ticked too.
However, I've never had one break, and I've put a LOT of rounds through my C8 since having the tac-latch put on. Enough to wear out one barrel, and about 10,000 rds into the second.
As for the ambi-mag release, I'm torn. Because of the design, the angle is bad for leverage, and it's a pain to release the mags. Not to mention, it's placed juuuuuuust a bit too far forward in my opinon, and I have big hands. I imagine it's a lot worse for someone with small hands. On the mag release though, I have yet to see anyone (right or left handed) drop the mag from their rifle because of the new mag release. The solution to that seems pretty simple too, hold the rifle out from your body an extra 1/2 inch.
So, what it comes down to is a matter of preference. Once again, we've seen that you can't make a modification that works for everybody (gee, who woulda thunk?

) It's too bad nobody in charge seems to learn that lesson every time we buy something (tac vest, small pack, C7A3, etc..)
I don't know why guys who hate the extra long lever of the new cocking handle would want a Badger Ordnance tac-latch. It sticks out about half as far. Sounds to me like guys chasing the LCF.
I was surprised to read about the weapons tech being charged for installing functioning parts on guns. Surprised and a bit angry at whoever charged him. Several years ago I was one of the first guys in my unit to figure out that you could put a C9 handle on the forearm of your C7, for an easy verticle grip. Almost immediately, I was threatened with a charge for modifying the weapon by a Mcpl, I think probably mostly because of jealousy.

So I researched the legality of the issue, and found out that ANY modification, temporary or permanent, is illegal, unless performed by a WEAPONS TECH. Simple enough. I took my C7 to the gun plumber & asked him to put the handle on.
Other than the tech thinking I was a complete idiot, it worked out pretty well. I never got to tell the Mcpl that it was "official," because he never confronted me on it again. Probably because within a couple days, the platoon WO had one on his gun.

From what I've read in this thread, the weapons tech who was charged was charged by another tech, so who knows what all that is about.
The moral of the story is if you want anything done to your gun, get the tech to do it. Even if it is something simple you can easily do yourself, you're better to have your bases covered, just like Leg says.
Cheers.
Tim