I use plasticell and like it. The buggest reason I bought it was because of the claim that wax moths can not destroy it. I've found that to be true. I had wax moth cover several frames I had sitting in my laundry room. They made a mess, destroyed the wax, but could not damage the begining shape of the cells imprinted on the foundation.
I have also found the bees prefer it over building from scratch. I had both plasticell and top bar frames, and the bees would not start on the top bar until it was their only option. Comparitively, they were much faster at getting a frame done on the plasticell. They could get most of both sides on a plasticell frame done in just a few days - while also working on other frames - but they would have atleast one frame finished in days. But compared to the top bar, and building from scratch, they worked on several frames for 11 days before having one frame almost done.
So I like it for strength, durability, helping to speed up comb building - no wires needed, or pins - and it's strong enough to take the spinning process in even the most harsh conditions of spinning out the honey.