The Rainier Arms Raptor is an excellent ambidextrous charging handle - I bought one for my Colt LE6940 I bought at WallyWorld.
It was $89.95 plus tax, but worth every penny. I agree with Fuzzee's review of it.
I haven't shot my Colt yet either - had to leave it behind for now until I complete my move; but I really liked the build quality and machining, and it worked great just doing function drills after I installed it.
I like how you can charge the gun using just your left hand, and not lose your grip on the weapon (I am right handed); I also like that you can use only one finger to operate the charging handle. The two finger grasp works fine too, but the Raptor really shines when you use only your support hand to both charge the weapon and to aim & shoot the weapon - simulating the loss of use of your strong side hand. If you did injure your arm or hand, you can still run the gun with your support side hand. Could save your a$$ in a real-life situation where you were injured....
I also installed a Geissele SSA two stage trigger to the Colt - the factory trigger was very gritty, had a lot of creep, and even after cleaning and re-lubing it, it still was pretty bad. So I just popped in the Geissele and was very glad I did, even though I only dry-fired the carbine with some Snap-Caps to test it out - huge improvement.
Then I replaced the factory Colt grip - which was pretty rough in appearance although suitable for use on a combat weapon - with Hogue's excellent overmolded grip and that was also a huge improvement over stock.
But the Raptor upgrade really added a lot of functionality to the weapon compared to the factory single-latch charging handle.
I would agree that it is an upgrade that any AR/M4 would benefit from - great improvement in functionality.
Nice post Fuzzee!