The difference between the Ultravid and the Trinovid is that in addition to the higher degree of Leica lens multi-coating, the Ultravids also have a highly reflective prism/mirror coating. Side by side, the Ultravids will be a bit brighter with more contrast, which is especially noticeable when viewing something against bright backgrounds. The Ultravid also has a much better focus wheel. I'm not positive, but I believe the UV is more waterproof and is nitrogen filled.
Roof prism with phase correcting coating P40 on the TV vs. Roof prism with phase correcting coating P40 and HighLux-System HLS on the UV.
HDC multicoating on the TV vs. HDC multicoating, AquaDura coating on outer lens on the UV.
That's about the only differences.