I have never had a Okanagan TC. From what I see on the forum, they are nice TCs. I have owned several TCs over the years, and bought my present 1988 Bigfoot TC in 2004. By far it has been the most maintenance free TC I have ever owned. Two windows needing recaulk during about 27 years, and never under cover, until last year. I am the second owner.
There may be TTs as good as the Bigfoot, but I really doubt any are better. I believe that to be true of the Northern Lite also. With few exceptions, the appliances are pretty much the same in all of them.
Wayne