I'm going to sing with the choir here. It depends on what you like.
I've done the Paul Gauguin, which is not a liveaboard. It's a very nice, and very expensive cruise ship that offers some diving (and, as we learned too late, you can also set up your own ahead of time). Accommodations are lovely, food is excellent, service is great, but you spend quite a bit of time at sea. If luxury and fine food is your thing, it gets gold stars for those. I thought the diving at most of the destinations was yawn-inducing. I don't like shark-feeding dives.
In contrast is my favorite liveaboard, which is the MV Tala in the Red Sea. It's not fancy (although I understand it has undergone some refurbishment since I was last there) but it's more than adequate and comfortable. The food varies with whether the usual cook is there, or has had to leave on a family emergency and has been replaced at short notice with someone who burns all the baked goods. But the diving . . . Red Sea diving is good, perhaps not as lush as the reefs in the Philippines, but certainly forthcoming with huge morays, turtles, dolphins, a few sharks, and lots of smaller reef fish. The wrecks are amazing -- even I enjoyed them, and I am not a wreck person. They are real, with history, and old enough to have a fair bit of marine life.
And the crew of the Tala is dedicated to the idea that every guest should peg the fun meter every single day. If you want to dive reefs, they'll put you on reefs. Wrecks? They'll put you on wrecks, and they have some fabulous 3D computer mockups of the wrecks to give you a superb orientation. Want to tech dive? They can support that. Want to scooter? Scootering three big wrecks in one dive at Abu Naha is a kick in the pants. Faisal will talk you into monkey diving and running a scooter with your toes. My husband has never forgotten that! And sitting out on the upper deck at night, under a sky absolutely milky with stars, is an experience I'll always remember.
It's surprisingly inexpensive, and definitely huge bang for the buck.
I would love to try one of the super expensive, fancy liveaboards someday, but I'm not sure any amount of polished wood and linen on the table will make a trip as memorable and just plain great as our two trips on the Tala have been.