Well I played with my Walnut Hollow extruder this past week. Not too bad. One thing I noticed was the extruder seemed to a little "scruffy". I don't want to say cheap as it feels solid enough when I work with it. The best way to describe it is the it looked kind of scratched and rough when I took it out of the box (not sure if I got a dud). I found that I got fine shavings of metal in my clay in the first batch that I extruded. It seemed like the extruder and been finished properly and the shavings came off with the first use. Needless to say I was using bronze clay and it didn't seem to really destroy anything. I made test scrap pieces and they fired OK. If you are concerned about this happening with your extruder, I would suggest running a bit of clay like Play Doh or other inexpensive clay to get any little metal bits out of the extruder before using it with clay.
Otherwise it seemed to work fine. Comments from last week suggest the Makin's Professional ClayCore Extruder Adaptors are supposed to work with this extruder. They are adaptor that give you the ability to create shapes with hollow cores. You can buy them through Shades of Clay. Supposedly they are great to make beads and I would imagine you can make great bails with it too. They come in sets of three. One package is 1 mm, 2mm and 3mm and the other contains 3.5mm, 4 mm and 4.5 mm. Add these to my wish list!