They have the same amazing feel that the addi Turbos do. They add about an inch to the length of the needle part because of the locking mechanism but other than that minute detail you have no clue that they are interchangeable while knitting.
I have knitted all sorts of different yarns with them and haven't had a single one snag at all. The only thing negative I would say about them is that due to the locking method im not sure how arthritis friendly they would be, and there is no size 5.
If anyone is in the Jacksonville, FL area I believe that A Stitch In Time
has two sets in stock.