It is going to come down to what you want to look at and live with in a window. Both are very good products with the edge toward to Okna in energy efficiency and in my opinion aesthetics in the Integrity.

+1, can't add much to that. If the appearance of the Okna is to your liking, you'll get better performance, better warranty, lower maintenance and cost. If the real wood interior is worth the premium to you, the Integrity is a very good choice. It all depends on your priorities :)

The Okna EnviroStar actually looks like a wood window when its installed. Many homeowners who live in older ( higher end neighborhoods) tell me they have an aversion to cinyl and demand wood. however, when i show them the Okna EnviroStar you would be shocked to find how many turn the corner and its never just based on price. its the performance as well as structural advantages of a higher end vinyl such as the Okna and last but not least, no maintenence. the EnviroStar is one of only a select few of higher end brands that can actually maintain or even enhance the integrity of a Tudor or older home.
as a side note, you may want to request seeing the okna with antique brass or brushed nickel hardware. its a real head turner.

the Infiniti is nice but the okna will beat it in both performance and price..
if you put the okna next to the infiniti you say both are pretty windows.

The Infinity has the same bones as the Integrity, just a little prettier. If you don't NEED the stained wood interior, the Okna is gonna be very hard to beat, and bests the Infinity in all measurable areas. It is about the closest thing that you'll find to "the total package", in terms of looks, performance, quality, etc... Should come in a bit cheaper than the Infinity as well.