How are you planning to install it? The Ultimak won't fit the loaded-model barrel, so I assume you're going to have a scope mount in the ordinary spot over the magazine/action. The sights you list will work for that, but it's a bit close to your eye and not the most typical mounting spot for them.
I have an Eotech 552 and I've owned and used Aimpoints the past. First off, the Eotech is a different technology, true holography, which is great - as long as it works. Eotechs don't have quite the bombproof reputation that Aimpoints (and ACOGs) have. Yes, they can be really solid and do see some military use, but I would not consider them as durable. Second, in precision the Eotech is superior - the center dot is smaller (about 1/3 MOA though it will appear about 1 MOA unless you have stellar eyesight) and I find the outer ring to help with speed. The Aimpoint in comparison is just one little dot, either 2 or 4 MOA. However, if you're mounting over the action, the design of the Eotech will raise the sight picture more than the lowest rings you could get for an Aimpoint, which may screw up your cheekweld. Finally, the Eotech has somewhat short battery life, claimed 500-1100 hours and possibly even less in real world use.
The Aimpoint is simple, well made, and older technology. It is extremely durable, and simple. Simple simple simple. It also has extremely long battery life on the order of 50,000+ hours depending on the model, which works out to years of continuous use. Most people who own them don't turn them off - no real reason to. It's also extremely pricey for what it is, IMHO, and a quality mount will add another $50-150 on top of whatever scope mount you need for the M1A itself. I can see the appeal given its extensive combat testing, but unless this is your ultimate SHTF setup, I would also consider a Vortex Strikefire, which for $150 is about 98% as good as a real Aimpoint. I sold my Aimpoint and will be keeping the Strikefire for a very long time.
You might also want to consider an ACOG, especially the low magnification compact ACOG models, as another high quality option that is durable and usable at close or medium range. The ACOG is basically a conventional scope with illumination, but it is an extremely high quality and durable scope, and the illumination plus clarity allows it to be used quickly at close range - google "bindon aiming concept." This is apples to oranges, but I would look into that option before buying the others. The ACOG is usually in the $900+ range, but SWFA has some discontinued compact models for $550. You will need to spend another $80 or so for a mount, however, so it will be more expensive than most Eotech or Aimpoint setups, though not by much over a good Aimpoint + quality mount.
