I upgraded from a set of Genelec 8020c's to these, and the difference is pretty amazing (and I loved the 8020c's, which are pretty respected monitors). The main reason for this upgrade was that the 8020c's really don't reproduce anything below 50Hz, and I found myself having to do most of my mixing in headphones for the bass frequencies. I considered getting a subwoofer for a long time, but it would be hard to position in my studio so instead I opted for new monitors.
As I had hoped, these monitors have really thick and smooth bass. However, the mids and highs are very clear and well-defined. The stereo imaging is also incredible and I could hear new details in beloved old tracks that I hadn't noticed before. And true to the mark of a good monitor, increasing the volume makes the sound feel "richer", not just "louder". According to my measurements in Room EQ Wizard, there is a slight roll-off on the high ends (>10kHz), but in practice the speakers sound extremely crisp on these frequencies.
Build quality is top-notch as you can expect from Genelec. I'm not using any of the built-in room correction stuff since I already have a solution in place for that. I appreciate that the speakers are still configurable even if you don't wire them up with ethernet cabling... there are toggle switches on the back for roll-off, volume, etc. So even though they are "smart" speakers they still behave very well when used in "dumb" mode.
They aren't cheap, but for the money they sound as good as you'd expect for the price.