The Vinylmax is not in the same category as the Okna and Soft-Lite products in this application.
The Soft-Lite Elements has some nice features and will give you a bit better structural (R-60 vs. R-50) ratings and slightly less air infiltration (0.01 vs. 0.02). Both of these number from either the Soft-Lite of the Okna far exceed just about every other window on the market.
The Okna Insul-tec will give you a bit better thermal data (U-Factor 0.25 vs. 0.26) and a bit higher Visible Transmittance (i.e. more glass) when compared to the Elements.
You can't miss with either window in this case.
Good options you have settled on here.