We've had HWH kick-downs on two Class C's. I'm not a fan. The jacks have never not extended. What rarely works properly is kick-down. The first C had four levers in a floor-mounted control box. I could operate each jack individually and I liked that. Especially when they didn't kick since I could wrestle one jack at a time. The current C deploys two jacks at a time. I also believe kick-downs don't add the degree of stability that direct-acting jacks would. So, just for me, Single-Manual-Control Direct-Acting. I hear good things about both HWH and Big Foot. The bottom-line Big Foot system uses a central pump like (most?) HWH.
Our 31-ft Jayco is steadier on the campsite since I installed Hellwig Sway Bars on both ends than it was when leveled using the HWH kick downs. And Sway Bars help while driving, Levelers don't. Often as not I put 2*8 boards down to drive up onto for leveling. I get less dirty handling them than crawling partway under the coach to pull a jack to vertical when it didn't kick.
Direct Acting? Sure. Kick Down? Think Twice.