I used those, until I decided I needed something that clamps on. They were ok. Mine is a leather padded deal similar to the one in the ad, but with a pair of AN-4s to clamp it where I want. I also haul around a machined block that fits the fuselage jack point. Since I use MS bolts, I don't need to use that one often.
I have that one shown from ebay. With my plane the brake lines run along the rear edge of the gear leg, with a section of it bonded to the gear leg with something strongly resembling 3M 5200.
Of course the tapered section of the jack point lined up perfectly so that it would crush my brake line. I ended up cutting the black adhesive loose and my IA glued it back after the annual.
In retrospect I could/should have padded the jack point with leather or plastic. This would have caused it to engage the shape of the gear leg below the bonded section and also not scratched the paint on the gear (even though that ship sailed a long time ago).
I got a bit of sticker shock when I priced aluminum gear legs from ACA. Besides the gun drilled brake lines they are one of the more significant weight savings I know of. I'm only quoting from memory but I think it was $4K for a set.
Well, I've been cured! At the Arlington airshow recently I saw a booth selling titanium gear legs for Cessna 180/185 for a mere $16k.
The guy in the booth explained that Cessna gets $18k for steel legs so I'm sure they sell plenty.