We've been using Ardex products for a while now. Been able to form a really nice relationship with Fishman's in Marietta and it's a great store. Ardex X4 is our main thin set. It's really a very consistent, quality product. The best feature with Ardex X4 is no slake time. What is 'slake' you ask? Well, when mixing thin set you're going to give it one initial mix...however much you need, with whatever amount of water the thin set (or grout) calls for. After this first mix you let the thin set 'slake' for 15 minutes. This slake time allows for a chemical reaction within the thin set or grout to occur. All the different parts of the thin set or grout need time to blend with the water and fire off. After 15 minutes is up you hit it with your mixer and it's ready. With Ardex thin set slaking isn't necessary so over a day if you're mixing four bags you can save an hour of waiting on thinset. We also love the working consistency and I think a lot of that has to do with the sand they use. The video below shows what I mean.  Best part, above all else, is that this thin set dries HARD. All that being said, know that a lot of thought goes into the material we use and we're thankful to have Ardex products in our bullpen!