In my continuing quest to find a microphone that emulates a KM-84 for less money, when I was given the opportunity to check these mics out, I quickly said, "Yes". This is a straight-ahead small diaphragm cardioid condenser that retails for $100.
I was doing a session the day after they came and after trying a few different mics on acoustic guitar (Earthworks TC-30Ks, Audio-Technica Pro 37Rs) I thought I'd throw up the Marshalls. Both the client and I were blown away! The top end was so present and in our face and was perfect for the guitarist we were tracking.
We ended up using the 603s for the session. Later, I looked a frequency graph of the mic and it shows a prominent boost centered around 9 kHz.
On another session I tried the 603 on snare (it was a quieter jazz-type drummer) through a Neve 1073 pre and it sounded killer. I tried the 603s as overheads on another session and didn't like 'em - too bright for that kit, but on older duller cymbals they might be perfect. For a street price of around $80 you just can't go wrong with these mics.

I ended up buying the pair of them. (www.mxlmics.com) -JB