VS,
The only one I am personally familiar with is the NAP 2000. It's what I have on my current rig. I set it up myself and found it easy to adjust and it is quiet. My brother in law has one alos, he had it installed at the shop. His does seem to have a "slap" sound to it when released. Mine has never done that, and I haven't examined his closely to determine why.
Others will join in soon on the models you've listed. You may even want to do a search here on them. I am sure they have been discussed in the past. Surely that will lead to more questions for you
