As usual, the answer depends on use and why you are looking at them. I have used a couple pair out if each line. I was looking for a lower cost binoc for travel. No idea about warranty, etc.
They aren't alpha glass. That said, they aren't going to give you a headache either. Decent field of view, good color and contrast, good light transmission, but they don't refine detail in dim light as well as a high price bin. Truthfully, they would work for 90% of glassing work and you wouldn't be missing anything. Where they lack a bit is at the edges of daylight. The Frontier are noticeably better than the Endurance, IMO.
They are competitive at their price point, and I thought had some of the better glass. GPO and Athlon were a small improvement, IMO. Athlon Cronus G2 were the best of the group, I thought. For a $400-500 bin. There are a lot of Chinese bins in this price point that are basically the same and are usable.
If you can go to $700-800, then Leica Trinovid and Meopta Meopro are very good and show up on sale in this price occasionally. Zeiss Conquests are also solid, but I don't see them on sale as often. These last three honestly give the "best" a hard enough run for their money that spending $3k becomes a very hard decision. This price point is the sweet spot in my opinion for value. One could be quite happy for a long time without spending more.
Jeremy
