Here's an in the room clip comparing 3 of them (XTC 101b, Uber Rev Green, Helios Eclipse
I have owned the Uberschall Rev Green, XTC 101b, Helios Eclipse, and Uber Ultra. I sold the Uber Ultra and the Helios Eclipse. The Rev Green is probably my favorite but it's almost closer to a Revf Dual Rectifier with Bogner DNA. XTC 101b has a very fun feel to it and is the most versatile from great cleans, leads, and chug capabilities. I am interested in trying the Snorkler and will probably pick one up at some point unless a new Bogner Fish preamp with the Cantrell mod comes out then will grab that. Uber Ultra sounded too filtered to me but could get the tightest of all the Bogners for Meshuggah level 7/8 string playing. Helios Eclipse was very balanced and sat between an XTC 101b and Uber Rev Green.