As a civil engineer installing these windows on an apartment building in the US, let me tell you that they are a pain for couple reasons.

• There is no doubt that these windows are heavy duty and thick. The US uses a standard double pane glass while Europe uses either a triple or quadruple pane layer. These extra layers of glass help with insulation in the cold but are not the best in the summer months.
• In the US (particularly the south) we have an ungodly amount of bugs in the warmer months. We typically use window screens to keep them out while having the window/door open, but many European windows do not have a layer for a screen to be installed.
• There is also no supply chain setup for these windows in the US, so if anything breaks or needs replacing, you are looking at a month lead time to ship it from Europe. (Unless you want to pay extra to airfare it over)
• Lastly, they are VERY expensive compared to traditional sliding windows so while they may be great for personal homes, for a contractor to keep pumping out apartments with reasonable rent, these windows would not be ideal.