If you want more specific information on the Pentax 10x50s, peruse the review at allbinos.com:
As with many Pentax porro models, the field is relatively flat, eye relief is very good (important for wearers of eyeglasses), but TFOV and AFOV is narrower than comparable models. Rugged construction is a plus for this line of binoculars, and the center focus is completely internal.
I don't have the 10x50, just the 20x60 which shares the same basic design. It's quite sturdy for the price, optically good, and I have been able to live with its compromises for astronomy use.
The Nikons and models from Oberwerk also come highly recommended from other users on CN, as you can see.
Good luck with your decision,
Thanks for the info. I think the narrower apparent field is going to be a deal breaker. My current binoculars have too narrow of an apparent field and that's one of the problems I'm hoping to address. I'd rather have a bit of edge distortion and a less claustrophobic view. Both Nikon and Oberwerk have a 65° afov so that's key info.
So to collate the information;
The Japanese Orion Ultraviews are highly thought of, but current (very recently) Chinese models are firmly in the "unknown quantity" category. I'll rule that out.
Nikon Action Extreme and Oberwerk seem to be more alike than different, filter threads can interfere with glasses but considering I'm already using big binoculars with filter threads and enjoy using the feature very much I'm 50/50 on it. And it's been pointed out that Oberwerk is frequently recommended purely from a customer support standpoint which is something I won't necessarily have backing me up with the Nikons. I've also been impressed by all the Obies I've looked through at star parties, although I've never seen that particular model.
There's a lone vote in favor of the Celestron EDs which certainly look appealing, but I'm leery for three reasons. My current bad binoculars are Celestron. Low end Celestron, but Celestron nonetheless. So far my only experience with Celestron binos has been negative. Secondly, slightly outside my budget, third I'm leery of light loss from roof prisms. I'd be paying a premium for more compact binoculars, which is something of limited necessity for me. I've always used Porros and when nature viewing I like the greater depth perception they provide. And slight CA doesn't bother me in binoculars so I'm tentatively ruling out the Celestron EDs.
So it's back to a toss-up between the Nikons and Obies with two key factors pushing towards the Oberwerks.
I think I've made my decision and I greatly appreciate everybody's input. This has been helpful.