While the BSS is reliable, I have seen two of them "off face" and they are surely over heavy.
I think someone offered the opinion that the Miroku 500 was a better gun than the BSS. For however little it might matter, I agree...Geo
Compared to what we find on the sxs market today, both the BSS and the Ithaca SKB are great guns for the money. Target shooters in general may prefer the BSS because it's heavier; field shooters the SKB because it's lighter when you're carrying more and shooting less. Both have very good single triggers.
The Miroku boxlocks, in general, are mostly preferred--IMO--by the same people who prefer the SKB over the BSS: Lighter gun for the field. Most of them also have double triggers and extractors, so less to go wrong (as Ted pointed out). Many of them are also more in the British tradition than are the Brownings and the SKB's, with straight grips and splinter forends. And while the Miroku-marked guns aren't quite the sleepers in the market that they used to be, they're also usually cheaper than BSS or an Ithaca SKB.