The easy way to mount optics on the M1A over the receiver have been solved.
http://www.bassettmachine.com/
http://www.youtube.com/watch?v=hHSMm6qcc9c
If you like a red dot sight such as an Aimpoint to co-witness with your iron sights, this might be of interest to you...
http://ultimak.com/m8.htm
( I just recently had the opportunity to handle one, and I will be adding the M8 rail to an LRB M14SA Tanker when I get back home.)
So easy that I blind caveman can do it.
I have had 2 different types of these Bassett mounts for well over a yr now, and both have performed as advertised. Simple, reliable, return to zero if the mount/optic combo is removed, then re-installed. ( I'm deployed now, and have one as a back up to what I'm using now on an M14 service rifle.)(Army Infantry since before the 1st war in the Gulf of Persia.)
It seems like you need to get a hold of both and see as to which rifle feels better in your mitts. Ergos, manual of arms, etc are slightly different between the 2, and one may fit you like a glove, while the other feels like a lopsided piece of 2x4. Both of the original designs were made for fighting, and both excel at it. While I feel that the M14 is the better tool for gunfighting, the AR may feel better for you. ( I have used both in fighting, and the AR types dont hold a candle to the M1A/M14, as I prefer it over the AR...... just as 5.56mm isn't even close to the 7.62x51mm is in terminal performance from the muzzle on out to the shooter's maximum effective range, cover reducing effects, etc....but thats a whole other topic......
Contrary to popular belief, a rifle does not require a pistol grip to be an effective weapon intended to be used in combat, defense, or hunting...... unless said pistol grip feels better for that specific person. The M1A/M14 allows a body to have either or. I prefer the older GI synthetic stocks personally, and also prefer them with 18ish bbls, such as the Scout model of M1A sports. ( I would avoid attempting to clear rooms by yourself regardless of the rifle of choice, as the reality of such endeavors is not pleasant, and even if you have a few buddies with you.)
So.... my vote may be towards the M1A Scout/Bush or M14S "Tanker", but still think that you should find out for yourself as to which one fits you best. I couldn't stop at 2, so .....
Having been familiar with the SR25 and M110 in past deployments, if your looking for utter reliability, then a well built M1A/M14S would be the route to go IMO. Hunting, fighting, SHTF, etc.... (I like the AR10 types for the range, but have not met one yet that I would trust for use as a defensive rifle.)
Quality magazines for the M1A run at around $20 to $25 each, and can be found rather easily on the net. I get mine from 44mag.com, as I know that they only sell the real CMI mags there, and if I have an issue with anything from them, they will make it right. ( Use the same mags at work in my issued M14, and they work dandy.)
Note: Not a gunbuilder, seller, scientist here. Just an "end user".
Good luck with your decision sir.
11B