I had to deal with this because my niece has a two year old that comes over to visit. I ended up going for one of these Barskas last year, which was an Amazon lightning deal for $197:
http://www.amazon.com/BARSKA-Quick-Access-Biometric-Rifle/dp/B005FDIUPE/ref=sr_1_2?m=ATVPDKIKX0DER&s=hunting-fishing&ie=UTF8&qid=1447629794&sr=1-2They are of course not really burglar resistant, other than smash and grab, but it works great for securing my bedroom HD shotgun and pistol when the kid is around. I was hesitant that the biometric feature would work well, but was very, very surprised at how well the Barska fingerprint reader works. From reviews, it's apparently much better than the Sentry readers at that cost point.
My trick for getting it to recognize me the first time everytime, was to use my thumb. When I did the initial scan, I jammed my thumb as far in the reader as I could, FIRMLY pressing my thumb tip into the back of the reader. That creates a reference point for me to ensure i place my thumb in the exact same place every time, and thus the safe opens every single time. It also comes with an external powerpack (aa batteries) so if the internals die, you unscrew an access plate on the door, insert the powerpack leads, scan as usual, and open the door. I'm still working on my first set of batteries from last year (probably time to swap them out).
It fits nicely into a corner without taking up much space. There's not a ton of room. I've played around, and can comfortably (criteria being that I can get them out fast without hanging up) a couple of HD shotguns with lights, or a shotgun and my M1A Scout. From reviews I've read, it is tight for an AR with 30 round or greater mag inserted. It does easily fit my M1A with 20rnd mag (pre-ban, for any ATF agents lurking). Your shotgun would have no problem fitting. There is a shelf that will fit a large or two small handguns. I've been looking at putting hangers of some sort in to hang a pistol or two from the walls, but haven't tried it yet.