I'd third the options listed above, it adds some reasonable backstory to the game. It also adds some good weapon mods useable again on NG+, if you're going back for a second go-round.
I'd suspect it'll go on-sale when the Omega DLC comes out, though if you're not hardcore ME fans, wait for the sale.
I enjoyed it and though it was second to LoTSB in quality and enjoyment value.
My DLC rankings across ME1, ME2 and ME3, from best to worst:
Bring Down The Sky
Price Of Revenge
I think that covers all of them.