Very comfortable to wear, the H390 looks the business, with faux-leather earcups and a padded headband. The USB connector is rather long and tends to get knocked; not ideal when listening to music on a laptop!
The sound quality is noticeably different to Logitech's older capacitive headphones, and I had to swap back and forth between my old pair and these for a while before I was able to persuade myself that new was better. In general I would say the sound is richer and definitely has more depth, but is perhaps slightly less sharp than some older Logitech headphones.
To note: the volume control is digital rather than capacitive, which means when you use the controls you are actually changing your PC's volume. As such, it has the annoying feature that it occasionally fails to work when watching videos in a brower, necessitating changing tab or exiting the program to adjust the volume on the headset. I would imagine this is due to the fact that the controls are attempting to adjust YouTube's volume levels instead and it doesn't work. This glitch aside, however, they are excellent and I appreciate the fact that companies like Logitech continue to include inline volume controls in their products.
The microphone is decently crisp; though definitely not professional-level it does well for online gaming and Skype. To note, while the product is advertised as having a 'mute button', this is in fact a microphone mute button and not for the headphones themselves.
Despite these niggles, the H390 is an excellent-quality set of headphones for the price and they come highly recommended.
UPDATE: After nearly two years of use one of the arms has become loose as a result of the small piece of plastic that clips it onto the headband snapping away. As it's seen daily use over around 22 months I'm not overly disappointed, though it does expose a slight design flaw; the frame of the arm is quite thin, with the bulk being an inlay which forms the interior of the design. If the frame is knocked or broken, the arm no longer ratchets effectively on the headband. I'll be ordering another H390 as I've been very happy with the audio quality.