I've never had the pleasure of actually shooting a side -by-side, but the one's I've hefted seem well up to the task of field use.

I shoot (quite well) an Ithica/SKB o/u 20ga and have killed a LOT of birds and many times more clays with it over the years.

That gun (originally my maternal grandfather's, before he died in '75) is quite simply an amazing shooter. 28" barrels, flawlessly balanced, and slicker than snot to operate. some I know like the sight picture of teh S/S better, but I have to shoot one-eyed (I know, I know... its just not happening, I'll explain later), and the S/S actually messes with my eye more than the o/u.

all in all, any good double is a fine weapon... its all in what works for you... now, would I COLLECT Over-Unders??? nah.