Can second the recommendation. When I was looking, I think it was the only USB-C/TB3 dock that supported multiple 4k displays at 60hz (one via Displayport and one via a USB-C to Displayport adapter). Their website looked a bit fly-by-night, but I've been happy with the product.
The only issue I've had is that my Macbook sometimes flips my two displays, but I believe that's an OS problem.
I can't speak to what else is on the market, but there's not more I'd want from this.