On the topic of CSS, it was overpowered in Fallout 3. IIRC not "100% Chameleon" OP, but still took all the effort from sneaking. However the New Vegas version is useless, it has no advantage over the Power Armor underwear. I hear it's supposed to make Stealth Boys last longer, but even if it worked i'd still say it should have an additional advantage over Recon Armor.
Personally i use the "Reinforced Stealth Suit" mod, stealth fieldless version. has too high DT by default, but that's what FNVEdit is for

Sure the AI doesn't mind being cheated, but personally i welcome a challenge, and i'd say the game is lacking it already. Just climbed to Black Mountain on Level 21: