Express/Explore are a little less expensive but consider also the cost of adding the brakes. By the time you add the 45 bucks for the brakes (55 for wide) you might actually be paying more. You want the brakes for resort skiing, and you can rely on the brakes to do the right thing a little more than you can on some of the other AT bindings. Besides which the straps they give you are seriously ugly. If you decide on the Express, having the shop deal with the brake at the time you first mount them is also a good idea.
One problem is that Freeride comes with the "standard" brakes that even with a little bending won't fit on a true fat ski (90+). You might be able to work that out with the shop, but if you buy online you might get stuck with a brake that's the wrong size for your ski and now getting rid of the old one and getting a new one is purely your problem.
The price point on the Express puzzles me frankly, 55 bucks up from the Diamir 3, for 40 grams less? Probably has more to do with how badly our currency blows vs the Euro in the last year rather than any functional advantage, and that same adjustment hasn't taken place on the Freeride price (yet).