I didn't spend much time on Nikons because while their Voyager series seems to be right there with Zeiss and Leica, they cost more. Their lower cost glasses don't seem to get the same respect at the places I was looking, so I crossed them off the list.
justdrivin, you hit it on the head.
The Pentaxs are an entirely different story from the affordable Nikons. They seem very well built and optically hold up really well when compared to the very best in the class. They are also less than half the money of the other top end glasses in the class. Except for edge focus, the Pentaxs seem to be the equal of the Zeiss and Leica if the subject is centered in the focal field. The Zeiss and Lieca glasses are both heavier than the Pentaxs, which make the Pentaxs more desireable if you're going birding or to an Indy car race all day (more likely for me). However, several people I have spoken to said that one of the reasons Leica and Zeiss are heavier and have slightly better optical performance is that they use denser glass that has higher content of certain minerals including lead. I'm not sure if that's optics mythology or if there's really something to it?
I'm also concerned about the Zeiss being a 10x glass. I was more sure until all the folks here posted about the shake thing. This actually makes the Leica and the Pentaxs more attractive as they're both available at an 8X magnifiction. But I like the ergos of the Zeiss better and the old fashioned roll down eye cups, as opposed to the newer pop up cups. I don't wear glasses yet as I'm only 40, so the extra shade provided to the pupil with the old eye cups is preferable to me.
When it comes to warranty, Leica seems the best in writing, although everyone seems to feel that if you hurt a Leica or a Zeiss, you will have to have tried real hard, and both companies will fix them at no charge. Leica makes it unconditional in writing with the Passport warranty, but Zeiss is supposed to stand behind their products no matter what from what I can tell. Here's where the Pentaxs are a sort of unknown entity. Japanese companies have traditionally been the worst about warranty claims in my experience.
I told my wife that I wanted either the Zeiss Classic 10x40s or the Pentax 10x42s as the top gift on my xmas list (that's not true, there was a new safe above that, but that's way too expensive). I'm not sure if she'll get me either (although I deserve them both!). If she gets either it'll remove me from the decision making process. That would be good. If I buy the Pentaxs for myself, I think I'd always wonder if the Zeiss really are worth the extra money and end up buying a pair of Zeiss or Leica a year or ten years down the line, just to reassure myself that I got the best. If they're a gift from my wife and they're the Pentaxs, I'll love them for the awesome binocs they are and never look back and we'll save nearly $400.00 in the process.
Life has led me to believe that if it seems to good to be true, then it probably is. The Pentax DCF WP series seems to be just that. Too good to be true. World class optics at upper mid range prices. Sort of like the Microtech of binoculars. When comparing a Chriss Reeve to a Microtech, the Reeve will usually win when the buyer is really critical and the measurements become really precise, but most folks would call them equals.
I'm still confused.
jmx