Having both the 3-20 and 3-20 Ultra Short, I can provide you with the following info;
See attached pictures. I purchased (special order) directly from S&B, a 3-20 Ultra Short. I purchased it with the intention of using it in both PRS type matches on a bolt rifle, and in Field type team matches on a precision AR platform. It took several months to get the Ultra Short because of the features I wanted. MSR Reticle, Capped Windage, and the seldom seen 14-mil per revolution DT turrets. The turrest are a special order for the US market, as the vocal minority here in the US demanded 17-mils per revolution, and S&B delivered what that vocal minority wanted. I had so many arguments with people insisting that the 14-mil per revolution turrets don't exist, or are not available on the Ultra Shorts, and even after showing them pictures, they would remain in denial.
Even though S&B offer quite a few options, they try to limit the number of features in scopes for the US market, as it's more difficult to catalog so many variations, and try to keep them in stock.
While waiting on my Ultra Short to arrive, I had the opportunity to trade a 5-25 with P4-F reticle for a 3-20 with Tremor 2 reticle. The P4-F was the last of a one-off reticle to my other S&B scopes with MSR and Gen 2 XL reticles. Having previously owned a 5-25 with Tremor 3, I found it to be way too busy for a Christmas Tree Reticle, and after studying the Tremor 2 diagram, I said to myself let's give it a try. I have since picked up another 3-20 with Tremor 2 Reticle. I like the uncluttered Christmas Tree Reticle, and find the wind dots more useful than a grid that is not only more cluttered, but needing to count 2/10 lines can get cumbersome when in a tight time limit. I personally think the grid type reticle's are more useful in a spotting scope over a rifle scope.
Back to the 3-20, when they first came out, I admit I kind of poo pooed them, mostly because they were more costly than the 5-25, and the LT/MTC turrets got a bad rap. Honestly, now that I have a couple, I like them. I even would like to get one with the MSR Reticle. The MTC is not as bad as the Premier Reticle scopes. The Ultra Short has an even better MTC, very smooth, noticable, but not overly tight.
The Ultra Short is fantastic, good glass, short, magnification ring a little more grippy than other models. However, the low profile turrets are not the best if you have aging eyes like me (another reason I chose the 14-mil per revolution turrets). The index lines are not tall enough, and take some extra focus of the eyes to operate. If anything that needs change in the Ultra Short, and that's the 2/10 Mil index markings on the turrets. I would prefer a little taller turret, so there's more purchase to grab ahold of, but that's one of those things that you'll have to get used to.
As you can see in the picture, the regular 3-20 is almost the same size as the Ultra Short with Sunshade installed.
As far as the MSR Reticle, I'm a big fan of it. In my opinion, it's the best reticle out there. I have not had a chance to look through a scope with the MSR 2 Reticle, but looking at the diagram and pictures, I think it would be better suited for higher power optics like the S&B 5-40, and would make a great ELR reticle. Time will only tell if they will offer the MSR 2 in the 3-20's?