I've got a pair and I posted my take on them on another site. Here's what I found in head to head comparisons:
Had a beautiful 65 degree day yesterday and I had little to do, so I decided to compare these great binos. All are mine, except for the SLC which I borrowed from the neighbor. I used my manfrotto tripod for steadiness, along with a resolution chart. My main goal was to justify or debunk the things we've been discussing lately. I have no bias whatsoever I assure you.
Build/Fit/Finish- I still believe the Trinovid to be the industry standard for toughness and this didn't change my mind. They, along with the SLC are rock solid and reliable. The GR HD also appear to have excellent build quality, they are heavier than today's norm (I like that), and the provided objective covers and lens covers fit extremely well, and is the best I've personally seen. I've had no issues with the Zen is this area except for the cheesy obj covers that want to fall off. Obviously this is easily fixed. Now on the subject of focus wheels, the GR is silky smooth, and the Trinovid and SLC are very close. The Zen isn't quite as smooth as the other three but it doesn't prohibit the use at all. As a matter of fact it's really a non issue. In this category I'd probably have to rank them like this........Trinovid, GR/SLC tie, Zen ED2.
Where the rubber meets the road (for me anyways):
Optics-I could not tell any difference between the SLC and the Trinovid here, so I'll lump the two together. They have excellent resolution and clarity. Colors appeared normal/accurate to me at all distances. The Zen is optically amazing. It is crystal clear, bright, slightly better resolution than the SLC/Trinovid, and colors seemed accurate to me. The real surprise/sleeper was the GR HD. While not quite as bright (very slightly) as the Zen, the colors really popped into focus. I'd say it had the most impressive view overall of all of them. I'd say the Zen had ever so slightly better resolution than the GR. Rank on pure optics......Zen, GR (very close), SLC/Trinovid. We all know that the Trinovid use technology over 20 years old. Considering this it is still amazing glass, and you would absolutely not ever be handicapped by using it against anything. All 4 got me well past dusk/legal shooting time.