Well then you have a couple ways to look at it;
1. Shoot all 12ga including slugs but not 3-1/2"
or
2. Shoot all 12ga including 3-1/2" but not slugs
3-1/2" gets mixed reviews, some saying it isn't worth the extra payload, some saying they don't pattern as well as 3" for whatever reason. Though some have had great results.
For all purpose including slugs, I'd go the 930. You mention comp and HD, have you seen the 22" JM Pro? It includes 3 chokes I think, extended Nordic magazine tube, Nordic barrel/magazine clamp, vent rib barrel with fiber optic front post and there's a model that comes in Kryptek typhoon/black.
Versatility in the 935 gives you the ability to fire 3-1/2" loads, but from my experience, it stops there and I have yet to feel like I need a 3-1/2" shell. The 3-1/2 is also more expensive and I've had a heck of a time putting loads/chokes together just with 3". I'm talking about an 835 and not a 935 but the barrels are the same. I like my 835 just fine and with the chokes and loads I've got, it's a hammer to about 40 yards. With a couple loads I can get to 50. I like it and honestly I'm not broken up about not having slugs as an option here. I have shot to deal with all manner and sized things, I have another 500 that is better suited for HD and closer stuff, and a 1911 should anything be THAT close and/or I have an empty shotgun magazine.
So those are my feelings, results may vary and what not. I won't steer you away from the 935, just that if slugs are important, I'd go another route.