I recently upgraded to the SA-50 from a Krell SACD Standard. Krell is known for its slamming bass but the SA-50 bass is just as slamming and more defined. An awesome upgrade and its now my reference. Synergistic Reseach just came out with footers called MIG's and only cost $150 and were especially made for the SA-50. These footers tighened up the bass and now it slams even more. Synergistic told me while getting ready for CES 2010, they compared the PO3, DO3, and Esoteric Rubidium Clock without MiG's to the SA-50 with MiG's. The SA50 with MiG's beat the PO3, DO3, Rubidium Clock combo hands down.