So, after what felt like years and years and years of waiting. I finally picked up my new MTH K4 with Proto 3. It was well worth the wait!
I had originally canceled my order in Oct when I picked up the Lionel version for a great price. I was very disappointed with the lionel version, tons of problems out of the box. I ended up returning the Lionel and re-ordering the MTH. Turned out to be a good decision. The MTH model looks great. Did a quick back and forth test run and all worked fine. Also, the whistle sound seems to be a huge improvement over past MTH releases. It seems to be louder and fuller sounding, if that makes any sense. Also when sitting idle there are a lot more background sounds that I never noticed on any other MTH Steamers.
I highly recommend picking one up!