I pretty much only ski behind our 99 E22 and love the wake. The wake is definitely bigger than our friend's 97 MC ProStar 205, but much softer to go through. It amazes me how much the MC wake hurts when cutting, my ski pops up a lot (and its not just me, my dad does it too, and he is a WAY better skiier than I am). The other boat I can compare it to is a 98 Ski Natique (20ft). This boat has a huge wake in comparison, but its super soft. I like the Epic wake the best, and it still throws up a fat wake at low speeds when Im boarding. I dont know how much of a difference the wake plate that 00+ E22s have makes, so next year I have to get a pull behind Steve (masonlk)'s 00 E22. If it makes a difference we plan to get it installed by a good fiberglass shop in Seattle, there are tons there.
To sum it up: (small to large)
Wake size: MC<E22<Natique
Wake firmness: Natique<E22<MC
Holeshot: MC<E22<Natique (this ones a little unfair as we have a 3-blade prop and the others both have 4-blades)
Interior: MC<Natique<<<<<E22 (no comparison, the Epics are way better)
Now mind you that the Natique is a closed bow, the MC and E22 are open. The Natique has the regular PCM 5.7L V8 (carb) engine and the MC has the Corvette 5.7L LT1 V8 (FI), but from what Ive seen and driven the E22 will still outrun the MC by a little and the Natique by a bunch.
Basically, the E21 is a great ski-only boat, get the E22 for a great compromise btw comfort and wake, and the X22 is an E22 with a tower and ballast tanks (that you can empty via rocker switches). I think the E22 and X22 wakes should be almost identical.
Ohh, and all of us ski at 15" off, about 4K RPM on the E22, 3400RPM on the MC, and I cant remember the Natique. Both my speedos are screwed (gotta fix that over the winter), but on the MC it shows about 34-35mph on both speedos (which the owner has calibrated).
Hope this helps a little