I have owned a 20 x 20 centennial kit.
Notice, past tense.
Ok, here are all of the things I didn't like about it:
1. The look. At first, I was like "whatever," but after a year of gigging with it, I started hating the "beer can" look of the kick drum.
2. It's a one-trick pony, meaning that in order to get a good sound out of it, you have to hit it pretty good. I play a lot of low-volume gigs, and in order to get all of that air from the batter to the reso, I had to play it too loudly to get a decent sound out of it. Feathering it or playing lightly just didn't work well. Sounded bad played lightly. It just sounded like the head, not the shell. I don't know if that makes sense or not.
3. Resale - Hard. To. Sell. I made a nice little flip on mine, but no one wants these. I'd thought about getting my kick cut down, but I didn't want to put anymore money in it. I ended up selling it for about half of what they are going for used at Guitar Center, Sam Ash, etc.
4. The feel - I've had two 20x20 kicks (One Centennial and one Basix birch), and I just don't like how they feel when I play them. I feel like I'm always having to stomp on it to get a decent sound. I had my front head ported, and the rebound is hard to describe. It wasn't bad or good; it was just weird-feeling. Sort of goes back to #2.
5. Doesn't really save on space - One always thinks that a 20" kick will save one space. While it can help with tom-mounting height, it doesn't save on depth. As a matter of fact, I have more room with a 22" x 18" kick than I do a 20" x 20". I also get a much-better sounding and feeling drum.
6. The shells are NOT the same a Maple Classics. Yes, these shells are made of American maple, and yes they have the Ludwig name on them, but they are are not the same. How do I know? Because I now own a set of Maple Classics and they are just in another league. I'll go into more detail upon request, but I'm afraid it'll deviate from the initial question.
Your mileage may vary on experience.
I've posted this before, but check out the depth difference of my 20x20 Centennail and my 20x14 Classic Maple: