2016 A20 is supposed to be a new hull/boat, so this is going to be a hard comparison for us keyboard jockeys. I can only compare the 2015 A20 vs the 2015 X-20 (I believe the x-20 will be mostly unchanged for 2016).
My opinion after spending dozens of hours on both:
Price: Axis by 2x (A20 = 55ish, x-20 100+)
comfort/layout = toss up, both are wide and feel bigger than 20 feet, both layouts are similar in design, the A20 will look plain, the x-20 looks high-end and is, comfort wise is preference.
Helm, driver lay out = A20, very comfortable and ergonomic, I hated the driver helm layout of the X-20, but I am sure someone else will feel the opposite.
Handling choppy water = x-20 hand down. Very deep V hull, cuts through the chop and rollers easily.
Handling for every other category, turning, driving straight, full ballast turning, sharp turns, small turn adjustments = A20 all day every day.
weight sensitivity, side to side = A20 is not sensitive, X-20 is horrible (remember deep V hull on the X-20)
Wakeboard wake = A20 hands down.
Surf wave = X-20, both are good, but the X-20 is built as a surf boat so I am giving this to the X-20 even though I was not impressed.
Freeboard = X-20
Bow Rise = X-20 complete fail. Terrible, almost un-driveable, almost
in cab noise = same
bimini = x-20. mastercrafts bimini's this year are amazing. The Axis is easy to fold up and stow, takes a minute, but the X-20 took like 20 seconds. It is rad.
board racks = X-20.
interior quality = x-20, but barely. I mean barely. It is not that impressive for a $100K + boat. The rear lockers are on small hinges with a single thin strut, the door shakes and rocks. Plastic everywhere, that pushes away easily. I could not believe how much there was. These are the same things people complain about the Axis, but the Axis does not hide this fact and is part of the reason some people (like myself) went with Axis. The vinyl quality is really good now with the new Axis boats, but the X-20 is better, more depth to the patterns, on looks alone, the x-20 looks a lot nicer. X-20 seats are more firm.
Adjustable interior= X20. The folding backward seat that lays down like the other MC's is awesome. easy to use, very fast. The A20 has a sliding seat that is convenient, but has no back to it. Not sure if the A20 will have the chillax seat option, but I hope so because I like it. the X-20 is a walk through bow.
warranties= X-20
amount of shiny metal = x-20
These boats, other than size, are completely different in most ways. If you can afford a $105,000 20' wakeboat, then test drive both and you will know. If you like the X-20 then buy it. If you don't and you buy the A20 instead, take the remaining $50,000 and go buy yourself a matching 2016 Dodge 1500 diesel tow truck. Then take the remaining $10,000 and put it in the bank.