Different skis have different strengths in different missions. There isn't one all-around best hydraulic ski. I have Fluidyne 3600s on my 180 and FliLite 3000s on my PA-12. here are some pros and cons.
Fluidyne Air Glide skis-
Pros- I can use 850s on the mains (not all Fluidynes can). The skis have excellent ground clearance when retracted. Installation and operation is straight forward, simple, and reliable. The ski uses the tire as a suspension cushion. Providing you have big enough skis your your conditions, they work just fine in soft and deep snow. Still in production so parts are available.
Cons- Heavy. When retracted the aircraft CG moves forward. The retracted position leaves the skis and rigging very close to the prop. Inspect that rigging thoroughly. When retracted the prop noise is reflected into the cabin. They don't turn well in the snow. Aft check cable rigging is concealed.
FliLites-
Pros- Big surface on the snow when the plates are closed. They float very well. No CG shift when operating the skis. Aft check rigging is exposed. The little tail wheel retracts with the plates so the ski surface is very clean when in the ski position. They handle very well in snow.
Cons- Heavy. Limited to 800s on the mains. Not much ground clearance. It can be a problem in the spring when a wheels-down runway or taxiway surface is soft. With wheels down the little tailwheel can't keep the ski tails high enough when pushing the plane back on dirt and gravel. Out of production and no longer supported by Wip, who owns the design and STCs. Parts are getting hard to come by. Installation may require significant gear modification on Cubs (attach fixtures interfere w/ HD gear).
Airglas skis are thermoplastic and while lighter than FliLites or Fluidynes they share some of the cons of the others. Ground clearance isn't good. The Airglas ski is very similar in concept to FliLites but the little tail wheel doesn't retract. It shares all the nuisance qualities when in wheels down position but also keeps that little wheel in the snow when in the ski position. Anyone with penetration ski experience can attest to the drag penalty (on snow) of those little wheels. It can make the difference between getting off or staying on the ground. Schneider ski guys who use plates often have to remove their little wheels for best performance. The fixed wheel on the tail of the Airglas hydraulic ski is a deal breaker for me. On a rag wing Pipers I'd say the old AWB 2500s are a darned good all around ski. Keep a look out for those, too. Or if money's no object, check into Rosti Fernandez skis. They're impressive. Whatever you buy, find out what parts are required for installation and make sure you get everything you need and/or that everything you need for your aircraft is even available. Many install parts are near impossible to find and can be prohibitively expensive if you do find them. Some ski deals aren't as good as they appear.
I know guys who have Fluidynes and at times wish they had FliLites and guys with FliLites that at times wish they had Fluidynes. FliLites float in powder better, Fluidynes are better when operating wheels down. Assess your needs, select what works best. Or more likely, buy the best skis you can afford and adapt to them. Bottom line, nothing outperforms a straight ski on the snow or in the air. Hydraulic skis are a performance compromise that come with a substantial weight and complexity penalty and at a price premium.