In my hierarchy the S1s and S2s would fall into the same bucket as mid-grade Nikons, Denver Redfields, and reborn Weavers.

I have five mounted on what I would consider to be 1st tier rifles. A 2.5-10x32 on a Winchester 70 Ultimate Shadow in 500 S&W and 4-12x40 AOs on a Marlin 917M2 in 17HM2, Remington 700 SPSs in 223 and 243, and a Weatherby Vanguard 2 in 6.5 Creedmoor.