Getting down to the nitty gritty about choosing, which one is easier to clean and maintain?

AR-10.

Though I view cleaning my M1A as a labor of love so it's not apples to apples in all fairness.

The AR can be cleaned from the breech which reduces potential damage to the bore/crown,and the chamber is more easily accessable for a proper scrubbing.
Downside is the scraping of carbon on the bolt carrier group,and all the Q-tipping.

Field stripping the AR is simpler.

Lube requirements for the AR are more straight forward.Breakfree in a light coat everywhere,and no worries about lubriplate in all the right spots.

The AR has no gas piston to fuss over.

With all that said,and even after having more than a few passing through my hands,I find the AR-10 a bit distastefull as a "Personal" rifle.
I'm more apt to treat it like an appliance or combination wrench.

The M14/M1A however is simply a joy with quirks that are easily accustomed to if you connect with the thing on a personal level.

If you are looking for a shoot,spritz,scrub,wipe and retire rifle.
The AR-10 is it.Same as the M-16/AR-15.

But then that's my .02.
S-28