Ithaca's aren't as popular as the 500, but they sure are drop dead sexy, in a simplist, Spartan kind of way... remind me of the scatterguns used during prohibition...
Anyway, they function as good as ANY other pump. Period. Ithaca has been around sometime and have always had an excellent reputation.
The model 37 defense, extended magazine with wood stocks is my next pump gun and will serve as the primary HD weapon alongside my Colt 1911.
Accessories are hard to come by... but when you've got such a damn cool gun, why clog it up with junk?!?! They can be had for $500.
Not many people own an Ithaca (compared to the 870 or 500), and that makes them that much more attractive, IMO. Make no mistake, their relative popularity is no sign of how well they're made. They are rock solid American shotguns... with few equals.