Summary: When I first started listening to this, it reminded me of the Sennheiser PX100. While the PX100 is open and this is closed, the warm detailed sound and tight bass seemed similar(but of course more bass on the HAS650 since it is closed). I don't have the PX200II(a closed version of the PX100) to compare it to. The sound on the HAS650 also reminded me of the HAS600, so I compared the two. The bass seems tighter on the HAS650 and there is also more detail.
Pros: Compact. Tighter bass and better sound than the HAS600. Very comfortable