There is nothing wrong with the Auto 5 ....and if that's what you want for a general purpose gun, that's what you should buy.
They were made as Remington model 11's / and as the Browning Auto 5's for almost a hundred years - from early 1900's - thru about 1998 or so. They did have some different models - Light, Magnum, etc - and the Auto 5 was made in 12ga, 16ga and 20ga ...and I looked it up(because I forget) but see they were made in 20", 26", 28" and 32" barrels.
We had a few Auto 5's in my family when I was a kid ...in 12ga and 16ga and 26", 28" and 32" barrels as I recall. I used to think they were a very good gun / but its pretty old technology these days ...still not bad ...just different. They have a "long recoil" system ...and it kind of "clunks" in and out of battery ...and in my mind, its fairly slow to cycle ....but if kept in good condition, clean and well lubed they are very reliable ( and they are nostalgic ) ....
The most versatile, in my mind, would be a later gun, made in the 1980's or 1990's with screw in chokes ...but if you want an older one ---that's up to you. The most versatile - for HD and fun would be a 12ga with a 26" or
28" barrel - and personally, I'd go for a 28". It isn't a "fighting" shotgun ..its a versatile gun ...that you can use for birds, clays, defense, etc ...
I see the other responses ...buy a pump gun ... ( in a tactical configuration ) ...but its my opinion, that most of those tactical or fighting guns go to the range twice a year - somebody puts 20 rds thru them ..and they go back in the safe. If you want a "fighting gun" buy the Benelli M-4, or a Rem 870 tactical or something ...... Buy the Auto 5 - if you want a nostalgic gun / like the feel of it ...and have some fun with it ...and in the one in a gazzillion chance you need it for defense, it'll be just fine.
I won't pretend to advise you on tactical shotguns - I'll leave that to the experts like DaveMc or scattergunbob ...they know what they're talking about. I have 25 or so shotguns ....all for fun, birds, clays, etc ..and nothing shorter than a 28" barrel / I can use them for defense if I need to ...but a 1911 handgun in .45 acp is the first weapon I'll reach for if I ever need one ...
good luck / and have fun with your search to find the gun that suits you the best.