I've fired about 15,000 Valkyries now, 0.28 and 0.25's. Not a single issue, very consistent.
I have a personal set of data on many makes BB's where I measure mass, size in 3 axis, molding marks, blemishes and internal voids and Valkyrie are very very good in all aspects I've measured. Personally I have swapped to Valkyrie for all but heavy BB's for which I use Novritsch's. I also would use Geoffs and G&G's. Valkyrie are bringing out heavy BB's shortly so I suspect they will be my sole provider then
Brands I avoid, Blasters (horrible random internal voids), Baddass, Snow Wolf, Cursed, draft club (airsoft operators box (boy are they bad!))
Hell, even cheapo Bulldogs are better than blasters (and much cheaper)