I shot some 24-gram Black Gold recently. Black Gold is a slightly hotter version of the White Gold. The 24-grams had pretty stout recoil from which I'd guesstimate they would be ~1350fps across the chrono (~1400fps MV).
I hardness tested the pellets and they were "medium" to "medium-soft". They claim that the polished shot helps it move through the choke and so give tighter patterns. Only one way to find out for sure and that is to do a 10-patterns test of course - which I haven't done. When it's warmer I'll do a chrono test and if they are genuinely quick I might do a pattern test.
It might also be worth doing a check of the pellet size. The UK#7.5 Black Gold I measured actually came out as ~UK6.75. Should have been 336 pellets, actually had 286 (nearer UK#6.75).
In 2004 I pellet counted and pattern tested Patriot F2 UK#7.5 24-gram shells (again with polished shot) and rather than the nominal 336 they had ~257 (nearer UK#6.5).
In 2005 I pellet counted a Blue Diamond UK#7.5 28-gram shell (also polished shot), instead of the nominal ~392 pellets (UK#7.5 28-gram) it had 357 (nearer UK#7).
So, from my experience the polished shot tends to be over-sized.
Used to be my only shell for sporting when new shells were affordable. Have shot countless flats. For me, they are as good as it gets. These days I only shoot them at tournaments. Still my favorite but lately B&P's are finding their way into my pocket. For Trap...good ole' Nitro's are still best of the bunch....IMO.