I've used multiple "multi-sight" systems, and I do highly recommend it as a great way to get more versatility out of a single platform.
- QD mounts on a big scope with folding irons & a QD on a red dot - This is what I'm using now on 2 of my rifles. If I hunt at night, I pull the big scope, put on the red dot. Takes 3 min, and comes back within 1/2MOA every time.
- Moderate or big scope with 45degree offset irons or red dot - have each of these on one rifle currently, both work well, but unnecessary if you don't need both immediately back to back. I snag those sights on F'ing EVERYTHING. Red dot off of the side works well for 3gun.
- Red dots & irons cowitnessed - doesn't really turn my crank, doesn't work with big scopes. Mall Ninja's swear by it for the tacops world they live in, but I want more magnification for hunting, and if it breaks, I go home, not hunt with irons.
- Red dot on top of a scope - doesn't work for me, cheek weld is poor, big objectives get in the way on a ring mount, wouldn't ever do it again.
What I would like to try next: Folding iron sights on a 45degree offset mount. MAYBE they wouldn't snag as much if I used folding sights, even though they'd be a little larger than fixed off-set sights. Wouldn't be as good as a red dot on the side for precision, but would be smaller and less likely to snag.