+1, similar to my story. Beyond energy efficiency, the sound reduction was amazing. We went with vinyl, for our house and neighborhood that's all we needed. As mentioned a few times, having them installed right (including proper insulation) is important. I might have done it myself but it would have taken me at least 6 weekends, and the crew did it all in one day. It was a local crew in the midwest, so can't help you with references.
Make sure you look into other convenience factors. Tilt-in cleaning for sure. Integrated locks so you can open the window a few inches but still be secure. The double hungs I eventually chose also gave the benefit of opening from the top or bottom, which I find important. We open them differently depending on time of year - for example, if the room is quite warm, opening a few from the top vents the hot air so the whole room cools, not just the bottom half of the room.