It's Alan, not Allen. I've been on one cruise with them, and twice on other ships where they had a goodly-sized group aboard. I'd go again but many of the packages he offers are on ships I don't want, or to places I don't want to go. And, like you, I need to find a person to share the cabin. Alan's e-mail list is so extensive that almost everything he offers sells out in a day or so, and I normally can't find anyone that quickly.
Someone (or 2, or 3 depending on the size of the group) people from his travel office go with each group. If Alan himself is along he throws a pretty nice party for the group one evening. He also offers only one shore excursion in each stop; it usually mirrors one of the more popular tours the ship offers, but at 1/2 to2/3 the price.
His price for the cruise itself is no better than you can get through any other agency; the savings, if any, come from the package of airfare/hotel/transfers/cruise.