The HP2 is way more finicky about amps than the L3k, imho. With the perfect amp, I may pick the grado. In most situations, it's all about the audio technica. If you're gonna build an amp around either, go L3000. If your'e not, go L3000. If you already have the perfect amp for the hp2, go hp2. If you want sterile rather than fun, go hp2.