With me they pushed the zirconium. Yes, zirconia is more durable (and hygenic) than acrylic, however, there are some important things for you to consider before you decide which material to have your teeth fabricated from. Clearchoice claims on their website that, for your convenience, ALL work is done under one roof. That is absolutely FALSE, especially if you go with zirconia. My teeth had to be sent to an off-site lab every single time I needed an adjustment. Furthermore, I had to wait six weeks to get them back each time; longer if they were backlogged. Keep in mind that you have a 3 year warranty (that's what it was as of 2017), so extended waiting periods for each off-site adjustment (which may or may not even fix the problem) eat away at that warranty period. Not to mention having to wear your temporary teeth again for 6 weeks or more (which basically aren't good for anything other than cosmetics). Believe me, it's a drag... especially if you have to have multiple adjustments in a row.
In my opinion zirconia is lackluster in appearance; it's too opaque. Unlike natural teeth, my teeth appear flat and dull and have no variegation whatsoever. In short, my teeth look fake! With a $48k price tag they should look like natural teeth!
One of the worst things about zirconia is the clicking sound that it makes when I chew. It's LOUD and it's annoying. Its basically like two solid rocks slamming into each other over and over (if both arches are zirconia). They kept telling me that everybody gets used to the noise, but I still haven't and I don't think I EVER will..!
In my opinion, acrylic looks MUCH more like natural teeth than zirconia. It's also a much softer material, so it's more flexible and there was no clicking noises when I chewed. [note: the first set and the trial sets are made from acrylic, which is why I'm familiar with both materials]. Acrylic just feels more comfortable all the way around. On the other hand, zirconium is very durable which means less breakage. Less breakage means less repairs and less visits to Clearchoice, less expense, etc. It's also nonporous so it doesn't harbour as much bacteria. So it's a trade off: Durability vs. Comfort and Appearance (not to mention the cost difference). It's a decision to consider carefully, but I wanted you to know what you're getting into with zirconium because they won't tell you about all the negatives up front (at least they didn't tell me)! I had to find out the hard way (pun intended)!