The price difference between the Accura and Optima is not very significant, depending on your budget and needs. There are several options to consider overall when making your purchase. The biggest question is the length of shots that you'll be making. I recommend the Optima for up to 150 yards, but after that the groups will open up a little bit, depending on how well you dial in your loads. Also, the Optima is a little lighter, in case you plan on doing a lot of walking with the gun. Also, the Optima comes with a stainless barrel, and there is not a Nitride coated option for this muzzleloader yet. For the Accura's, the difference between the MR and V2 is pretty minor. The V2 is incredibly accurate out to at least 250 yards, and has the thumbhole stock that many people enjoy. The V2's are drilled and tapped for scopes AND open sights, regardless of which option of the rifle you buy. The MR is only drilled for a scope, which limits you in some states.
If you're only hunting casually with a muzzleloader, or are just getting into it, the Optima would probably be a better choice starting out. However, if you plan on doing a lot of muzzleloading, the Accura may be the better choice, and a lot of people really like the Nitride barrels for the extra weatherproofing. Either way, you're going to get a great muzzleloader, and both use the CVA QRBP breech plugs, which is probably my favorite feature of the CVA lineup. Let us know what you end up choosing!