Anybody ever use something like this? Or have something better?

Looks pretty specialized for some trades.

I know a few who have them. If it fits a need for you, they are good systems.

I have large dog box and so it takes up too much room to be functional for what I need.

I want one but I also hate the idea of giving up depth in the bed. I know alot of bird hunters will run this with a camper shell and dog boxes on top.

Similar to this

I have had the Decked system for almost 2 years on a 2022 F 150. I really like it for going to the range. Cased rifles in the drawers and range box strapped on the top. Keeps thing dry and secure. I can remove it in about 10 minutes max with a battery impact so if I need to haul firewood or a trip to Lowes no problems.
No downside to me. My son (who can break an anvil) let one on the drawer's fly shut at full speed on a full 45 % slope. The drawer cracked by the handle but would still work. I sent a picture to Decked and within 2 days I had a replacement via UPS. No issues since then.

Is it waterproof AND dust proof i live on gravel

Those are relatively small dog boxes, works well for some, not for others.

In the video - he says they're mediums, good for a 70lb lab or bigger GSP. Dunno, I don't have any to really know.

I've had a bunch of dog crates. Those medium ruff tuffs would be tight for 70# dog. I had a large and it was fine for a 75# dog, but wouldn't fit under that topper.

Those medium may work if you are driving 10 miles down the road to the reserve, but if you are driving 1100 miles to north Dakota, it's a different story.

IA, no problems with water or dust yet. I have a gravely driveway at home and at work and haven’t notice any dust at all inside the drawers.

One place I worked had RimRock's in their pickups. They were awesome. You could put whatever you wanted on top of them and bounce 2,000 foot up a mountain on a pioneered road.

RimRock Toolbox Link

I've had the Decked system on my 22 Ram 2500 for the last 18 months. Overall, I have zero regrets. The main advantage is hauling rifles out of sight and out of mind.

Only downside is if you are regularly having yards of dirt or mulch but for me, that's rare enough to not be a concern.

My youngest has a similar setup.
It's kind of a specialty. Works like a champ for some folks. Some folks wouldn't have one on a bet! LOL!
The kid has a camper shell with that in the bed.
Biggest inconvenience is that if you want something from the very front, you literally have to "crawl" up into the camper.
The drawers are quite convenient.

I know they aren't for everyone but I love my Ridgeline. Lockable bed trunk is one of its great features. The tailgate that opens two ways is super handy, too.