I do not know anything about the Kolbe Vistaluxe and would need some time this evening to read thru you post better in hopes of offering useful info.

@millworkman thank you so much. As far as I know Kolbe Vistaluxe seems very similar in construction to K-Ultra. Here is link (http://www.kolbe-kolbe.com/products/index.cfm?pcID=4&pID=57&pSeries=6) and beginning of Kolbe marketing description:

"VistaLuxe® Collection products were developed in
collaboration with architects who specialize in contemporary projects.
As a result, it meets the aesthetic of clean lines and multiple units
with large expanses of glass, while offering a warm, organic wood
interior."

I think it was introduced late 2013.

Ah now I see what it is. They have streamlined the Ultra product for a more modern look with narrower sightlines. I will take a better look and try and answer your questions better this evening.

@millworkman again thanks. Vistaluxe is not likely to be within budget so you can ignore it for me, but might be interested in knowing for yourself. I just spoke with the Kolbe dealer for my area and he indicated that Kolbe is only selling Vistaluxe through a few select dealers (not him) and that he had priced it for a client and it was 25-30% more than Kolbe Ultra.

Not surprising as it needs to be beefed up to be able to support the thinner profiles

My original ?s are still unanswered and I'd love any responses. The only thing changed from my OP is that I have probably eliminated Kolbe Vistaluxe which seems great for a modern house due to likely cost being > Kolbe Ultra by perhaps 25%. I continue to research Loewen and am surprised that some well respected window gurus on the forum rate is a meaningful step down from Marvin and Kolbe. Loewen as a standard uses douglas fir throughout and their website page indicates (http://www.loewen.com/app/loewen/test/windows/features/douglasFir/index.html) its > impact and compression strength and resistance to rot compared to ponderosa pine which if I am not mistaken is what Marvin and Kolbe use unless you pay for an upgrade.

I'd suggest looking at the windows in person and get pricing. That may narrow the field some.

Don't necessarily want to get into technical detail "debate" but Loewen claims to use Coastal Douglas Fir. The April 2010 Forest Service labs Woodhandbook (http://www.fpl.fs.fed.us/documnts/fplgtr/fpl_gtr190.pdf) does NOT test vertical grain DF as a category; Loewen website simply cites the handbook findings and seems to be in ballpark of accurate in claiming that their DF has better performance characteristics to Ponderosa Pine IF I am understanding things correctly.

While I am interested in performance numbers and especially glazing performance, I am equally interested in forum "expert" opinions on functionality, customer experience, warranty service, etc.

Thanks for any other input. And yes I will seek out looking at more things live, but while that is what I see and touch, it is what is under the hood that probably will have greatest influence on long term satisfaction.

Well my posting about Vertical Grain and Flat Grain was more to do with aesthetics as if you see a Loewen with Flat Grain DF it very well may look nasty as Flat Grain can be nasty looking.

@millworkman any visual comparison of Loewen flat grain DF and whatever Marvin or Kolbe use as their entry standard level wood (ponderosa pine??); since I expect that I will stain the wood rather than paint it the grain appearance would be important so thanks for what you have pointed out already.

I will say and I have seen this myself, that sample windows may not always be representative of exactly what you may end up with. I have seen pitch pockets in customers windows and seldom have ever seen them in a showroom sample. Rarely is a sample just picked off the line as your dealing with made to order windows as they do not have stock product. I will have to see if I have any pictures of the wood/grain types. You also need to remember what may look awful to you very well may be seen as the "natural beauty of wood" to the manufacturer.

Vertical grain would be the best for stain uniformity. Consider mahoganey as well. Keep in mind some stain color can be hard to acheive with some species and you may want to get some samples first.

This was interesting to read, as we have had Loewen windows and doors for about a year. The interiors are finished with clear Rubio Monocoat. I just went and checked the wood grain in several rooms and all of those had what looks to me like VG fir for the glazed panels/doors. There is some mixed/flat grain on the jambs(?). Never noticed anything "nasty" on the windows/doors (and we have lots and lots of them) but maybe we were just lucky or I am not very discerning.

Oaktown, I am considering Loewen fir and finishing with with Rubio Monocoat. Did you monocoat them yourself? Are the sashes and frames tight to the glass? Were you able to oil them without having any oil drip behind the sashes. I have had this happen with paint and it looks terrible from the outside and you can see it at the porch windows. I have years of monocoat experience doing floors and furniture but not windows.