The Amphibian and the Badlander are essentially the same gun just a different finish.
AWC make one fine surpressed weapon(s). I have shot these guns as well as their Surpressed 10/22 and MKII/77. All great shooters.
I work in a gun shop part time and we are a ClassIII dealer so I get to play occasionally.
AWC will also build one of these guns with your Ruger MK, Saves you a little money. You can also have them thread on of your MK's and then use one of their "cans" (The Arcangle T is outstanding) and have the best of both worlds...
I have purchased 3 intragally suppressed firearms from SRT arms in AZ. The ruger MK series suppressor he makes is a pleasure to shot and has been very reliable. SRT is a great to deal with, you call or email and you will get a response in an hour or less. I would highly recommend checking out what he sells. www.srtarms.com