Teesquare did a great job explaining some of the differences. The good news is all three of those grills are made in the U.S.A. which is a win, win, win!!!
I have not cooked on either a Yoder or the Grid Iron, so I cannot give a comparison from that perspective, but I can address a couple of concerns you have about the MAK.
...I have read great things about the Mak but want to ensure that it is worth the extra cost.
The two biggest factors in the price difference that get overlooked, because they're not obvious, are: Shipping and the Metal used.
Metal: Rather than mild steel for the body, MAK is using
Aluminized Steel (for its corrosion resistance) with a 1200° powder coat finish. The critical components are made of 304 grade Stainless steel. This adds to the cost, but it should virtually never rust.
Shipping: Shipping cost is included in the price of a MAK. As far as I know, unless you live close to a dealer, you will pay around $100 or so for shipping on the other two grills.
BTW - When checking pricing be sure to call a MAK dealer. You will get better pricing ordering from a dealer than directly from MAK. MAK does this to to guarantee that they do not undercut their dealers.
My number one concern with the Mak was the size. It seems so much smaller than the Yoder for example. However, it sounds like the Mak has plenty of usable space with the full upper rack.
Yes, The MAK has deceptively small footprint. When we first got our MAK 1 Star I was a little underwhelmed at how small it seemed. It wasn't until I did a couple large cooks that I fully appreciated just how much room it truly has (because of the lid design) and how much food it can hold.
I do a few large cooks for large crowds every year. I have no problems cooking 8 butts (4 full sized butts on the bottom - 2 full sized and 2 smaller (7 lb) butts on the top).
How about 80 pieces of chicken or 40 leg quarters?
Hope this helps answer your questions on the MAK if that's where you're leaning.