Years ago, I got DisplayFusion on Steam. It helps a LOT with multiple monitors - and even with just one, it has some nice features. Other products since then were added to my library.
The greatest advantage, though, is that the support seems to not use pre-made texts, but understands that directly responding to your problem saves time for both parties. Every answer I had to this big software with all the many, many features, was answered quickly and in detail. It also seems that critique and feature suggestions are welcome.
All in all great products with a good customer relationship, so to speak!