Skellig Eco Tour Operators Recommendations

We went with SkelligWalker (http://skelligwalker.ie/), were delighted with the trip, and would recommend them wholeheartedly. Yes, there is a "marine head" on the boat (though I don't recall if either of us used it - so if we did, it wasn't particularly memorable). It's a good-sized boat. They do both landing trips and the non-landing "eco tours" (we did the "landing tour" but in order to space out the boats landing and departing, we spent about 45 minutes touring around Little Skellig first). It was all very cool.