For RLV users wishing to try-out the new Viewer 3 UI, there is news: Marine Kelley already has a version of RLV out which incorporates the new UI and other bits.

The Viewer, built on the 3.2.2 (0) release of November 7th, includes the new UI presentation of buttons, notifications appearing up in the top right corner (see image), Destination Guide open by default, and so on.
Additionally, it retains the RLV menu option and includes a couple of familiar sliders seen in other TPVs up in the Navigation Bar: the avatar offset and the Draw Distance (the latter of which I’ve always appreciated in those TPVs that have it in difference to a Quick Preferences button), as well as including the ABOUT LAND and SKY buttons.
Unlike the latest versions of the official Viewer, the mini-location bar is displayed in addition to the Navigation Bar / Favourites Bar, rather than the option allowing you to toggle between the Navigation / Favourites and the Mini-location. Being the (0) release means the Viewer doesn’t have the new snapshot floater – but given the speed with which Marine got this version out, one supporting the floater may not be far behind!
Performance-wise, on my usual machine the Viewer is on a par with the latest 3.2.2 release, coming in with an average fps around 20-22. Some have reported teleport issues with 3.2, I’ve not encountered any myself – and certain none in this Viewer while hopping around the place.
There’s not a lot to review here that I’ve not covered elsewhere when it comes to the new UI (see the link at the top of this post). All I can say is, kudos to Marine on the speed of her response with the release, and if you are curious about the new UI and want to give it a go but don’t want to crack out of RLV – now you can!