I've seen some of their bottleneck stuff come through my recycling stream and it has been as good as any other, but the only "rifle" case I have gotten from them new has been 30 carbine and while it is a tapered case (and thus technically not "straight wall"), I don't think that's what you're asking about.
But, all of my 30 carbine brass is formed into 5.7mm Johnson cases, which are bottleneck cases, and the Starline brass outperforms both previously fired-brass as well as new Norma brass in that the mouths are less likely to split and the cases less likely to emerge from forming with an eccentricity attributable to uneven flow of the brass during forming. And since I assume Starline's chemical composition of their brass and their metallurgical techniques are no less sophisticated on bottleneck cases than on pistol/carbine cases, my experience turning carbine brass in to 5.7 brass probably suggests their rifle brass would also be first-rate.