"Deore is not next to the bottom !" You still have Alivio, Acera, Altus, and Tourney. Deore is the start of the real deal in parts. And not only is it the real deal, but they are cheap, work very well and hold up to extreme riding. Out of the many bikes I own, just to give you a idea. I have one MTN bike with standard Deore components and another with full blown XT. While I will admit, when the XT bike is "fully tuned" works way better then the Deore bike. The Deore bike requires "Waaaaay" less maintenance. So unless you are racing, Deore is more than fine.

But to give you the latest break down from best to worst. XTR, XT SLX, Deore,Alivio,Acera,Altus,Tourney. And in the previous years,LX now renamed by SLX was just above Deore. Now the new LX stuff is for treking, whatever that is supossed to be.