I picked up a 3 pack of the 604's thinking it would be a great solution to mic placement on drums AND the great Sennheiser sound I've come to know and love over the last 20 years. Well, after "test driving" them both live and in the studio I'm afraid they aren't all I'd hoped for. First, as far as placement goes, they are great. Nice and small, they tuck right in and don't protrude the way a lot of mics will (especially on drums). The plastic mounting clips are a little cheesy and I don't expect them to last very long. On toms they sound pretty darn good - they are no MD 341, but considering a 3 pack of these little gems costs less than 1 MD 341 I wasn't expecting them to. I loved 'em on live gigs, but for studio tracks they are a little flat sounding. However, on a snare drum I was not impressed. Ironically that is where I really need help with the placement issue, but the sound was just too harsh for my taste and I tried the mic on 3 different snare drums. I had to pull out the ol' trusty SM57 for THAT snare sound. It still gets in the way, but it handles a snare better in my opinion. Overall I do like them, and for the price they are hard to beat. I'll still use them on my toms for all my live gigs, but I'll be saving my dough for some higher end studio mics. A good mic and a good deal for the price, but don't expect miracles. Of course your mileage may vary...