HSMITH, as usual, nailed it.
What goal do you have in shooting skeet?
Some shoot to improve hunting skills, others have that itch to compete. I started out with the former in mind--ended up doing the later.
I prefer the 12 ga, with a 28" bbl or longer. Reloading allows for tailoring loads. One can load 7/8 oz loads--which will run fine in an shucker, might not in an auto. Just a bit more versatile if one only has one gun, IMO.
If you hunt , decide to try other clay games etc, the extra payload of a 12 can have an advantage. That said I've shot a bunch clays with 20 ga-- heck even 28 ga at S/C and Trap.
Gun fit is most important --regardless of platform. Gun fit, practice, asking for/getting
quality lessons ,dry fire and swinging the gun.
I used to swing through all the stages in my garage/ extra bedroom. I'd add weight to strengthen/gain staimina. Yeah, my ex thought I was nuts too...she changed her mind though...err on my practice anyway.
Be careful in getting caught up with the gun buying/switching/shooting the brand name/platform...etc. One cannot 'buy targets", its the shooter with a gun that fits and practices that hits--always.
Some rationalize a new gun/platform--because so and so uses it. Others want "this" new gun/platform and rationalize/need others to shoot "this" gun/platform . Qualifying a purchase.
My shooting partner ( personal DR also) is an example of one whom though he has won a bunch of medals at the World Shoot,doesn't compete anymore. He shoots a pump, with the same gun he still runs straights at skeet/trap. Kills ducks and geese, even took a deer last season.
I have a lot of people I know that use pumps.
Instead of spending $ 1k on a gun...many would be better off with an 870 Express ( or a used pump/auto) and using the balance left over to purchase a Mec single stage , lessons, and getting a proper gun fit--IMO
Another thing, don't take it (skeet) or yourself too seriously. Sometimes one has to have fun, poke fun at oneself.For instance- One can bang/shove/curse a door that won't open--step back and realize duh...turn the knob, laugh at yourself and go through the door
"Beware the man whom shoots one gun". Is a very true statement.