Does anyone have experience with these?

Looking at these ==> https://www.prestacycle.com/product/...-9-12-freehub/

.

Not sure if 269 price justifies the weight saving (?)

I bought one in 11 speed (fwiw it was $100 less than the 12s seems to be now), but haven't put it on the bike yet.

Some info in this thread: Lightweight CNC close ratio 11s cassette?

Not looking to save weight, need a cassette for alternate wheel and don’t want to pay for SR.

.

I don't have Campagnolo or a 12-speed drivetrain, but I have 3 Uniblock cassettes (12-28, 12-28, 11-34) for Shimano 11-speed freehub, of which only the first is currently installed. The second is a spare, and the third is about to go on my new gravel wheels.

With a mechanical 105 medium cage rear derailleur (RD-5800-GS), the shifts on the Uniblock 12-28 are indistinguishable from Ultegra 12-25 and 11-28. This is my riding impression over the 6 months (< 1K miles) since I bought the cassette.

All of my cassettes are Edco Prestacycle uni/monoblock cassettes.

On the one 10 speed 11-32 I owned, the 32 tooth cog folded at a shift ramp on a massive high torque cross-chained shift. I did the rest of the ride on the smaller 9 remaining cogs. I bent it back and it was fine from then on...Maybe not the cassettes fault?

Every other one 11 speed 11-28 to 11 speed 11-42 has been flawless. Just be sure to get the proper 10-11 locknut if you intend to run it on a 10 speed freehub. The proper locknut is a millimeter or two longer than the 11-12 locknut for 11 speed freehub bodies.

Easy way to save some weight & some cash over XTR/Dura-Ace level components & no individual cogs to kill uber-light aluminum freehub bodies.

FWIW: Shimano, Campy, & Sram 11 speed cassettes are all the same enough spacing & width to be functionally interchangeable. Buy whatever one fits your freehub body. If A=B & B=C, then C=A

Absolutely worth it IMO.

On a related note: 11 speed mountain is 11 speed mountain. Buy whatever derailleur is on special. Here I have an Ultegra 6800 road shifter routed to a Wolftooth TanPan to convert to Shimano 11speed mountain pull ratio, running a 11 speed SRAM GX derailleur on a 11 speed XT 11-40 (42?) cassette.

If you're willing to shop overseas, SR is about the same price, and Chorus cassette would be lot less expensive.

Basic question of why you are even considering SR. They wear faster and Chorus shifts exactly the same and cost a LOT less. There are places where it might be worth paying for SR, but cassettes are certainly not one of them.