These screws are rock solid. They are incredibly fast to place. They are super easy to "start" and then they sink into the ice like a drill. In my experience they are easier to place then BD turbo express. Now, the sling: Ok it's great in a way, and also quite limiting in a way. It's nice (at least psychologically) to be able to clip in after just two rounds of turning and it's nice to save a carabiner. On the other hand if you want to use a long sling you either have to clip a carabiner to a carabiner (!) or plan it in advance and rack it with the long sling attached two one of the two clipping points. They are quite tricky to rack as well.
So, these screws are great, especially in combination with others, but I would not recommend a rack consisting of only these.