Thoughts?

I vote for the PWS. Easier/cheaper to mount optics to and a more robust piston system.

Also gains cheaper magazines and even lighter ones. Easier to suppress as well.

I used to run M-14's/M1A's pretty heavily.  Now, my primary 7.62 is the PWS Mk216.  Here are my thoughts:

Can M-14's be made to be accurate?  Extremely accurate?  Yes... Absolutely.  However, it's going to take a lot of work, by someone that knows what they're doing.  It's also going to take a lot of work to keep it running that accurately.  If you're asking this question, quite frankly, you don't have the expertise to do this.  That's not a shot against you, that's just saying it takes years of experience and if you had it, you'd be doing it right now.  

Optics?  It's a pain in the ass with the M-14 unless you go with a chassis.  They work well... But it's HEAVY, and awkward.

Aftermarket gear?  No comparison... The AR/SR-25 system is like the Barbie of rifles.

Mags?  The MagPul SR-25 type mags make it a no brainer.  A lot of people consider the M-14 mags to be a superior design (Why?  I have no idea), however there's nothing wrong with SR-25 type mags.  Check-Mate M-14 mags are mil-spec, high quality and readily available... However, the MagPuls are cheaper and work great.

Reliability?  I've run the absolute shit out of PWS rifles in shitty conditions... wet, dry, muddy, etc. and they just work... And keep working.  M-14's are also extremely reliable, except for the fact the the SOCOM is largely made with civilian cast parts and USGI parts are getting harder to find.

Is the SOCOM a good rifle?  Sure... But it's going to require a lot more work than the PWS to give you the same level of performance.  With the PWS you just take it out of the box, load mags and pull the trigger.

Just my opinion.