[Imp]

It can work if expect radar air defence SEAD are vital.
Verses MANPADS the thing is to locate them often the hard way then hit them with arty or smoke out if do not have TI. Use terrain to your advantage like streams etc to fly down dropping smoke where its open. Obviosly no terrain to hide behind is not helo country the more hills terrain feautures the better.
Apart from your Air Cav attack helos I generaly buy in pairs with a scout helo for each.
It tests the water & checks out LOS for targets rather than moving attack helo & finding no shot.
It can work I remember a river crossing in which I let the AI buy my force, nearly all air & arty with a few ground units who made it over the river easy as Air Cav cleared the bank. Vs AI mind & the comment about AI not moving its AA seems wrong to me. Not played it for a while but it moves both SAMs & Mobile AA guns.
The thing to remember is yes they may be fast but really treat as armed trucks so take care on the approach. Vs a human use the if a decent sized map attack one place hopefully drawing his forces in then use your speed to shift to the real attack position. If you can get a hill between the 2 those MANPADS are twidling there thumbs.