We reviewed a quote for 11 Okna 500 insert replacement windows with deluxe foam upgrade and internal grids for $780 per window installed. Around $8,600 with almost 2g being install and 1g recapping windows after install. I can upgrade to the 600 series with composite reinforcement in the sash and a better seal system on the bottom sash for $45 per window. Do you think it worth $45 per window upgrade for the 600 series? Also is it worth the upgrade for full screens? I just had a VinylMax Edison estimate for just under $5,000. What bothers me about VinylMax is a 10 yr warranty - I read if they offer a 10 yr warranty it is because that is how long they expect their window to last. The Okna windows are literally double with all the upgrades but has a lifetime warranty.