[Edited for usefulness on 11/15]
I can't bring myself to be super-critical of the Samson C02, because in spite of my occasional dissatisfaction it does have a lot going for it. I've had my pair for about a year, and I use them frequently as overheads on the drum kit, on acoustic guitar, and as "room sound" mics for vocals.
For the latter two applications they are adequate, or at least I can't complain. Unfortunately as drum overheads they have been disappointing, and this is what I primarily wanted to use them for. To my ears they sound a little thin and lack presence and clarity, especially on cymbals. I like the overheads to get a detailed overall picture of the drum kit, so that's a drag. Another bummer is that there are no switches on the mic - something like a bass cut or -10dB pad would have been nice. Without a pad switch, putting this mic under a snare drum is a recipe for disaster. Or maybe you could just ask the drummer to play quieter?
So I guess when it comes to small-diaphragm condensers I still haven't found what I'm looking for. The bad news is that the $400-$700 price bracket is apparently where I have to look next. On most of my projects over the last year I have been able to use a famous similar type of microphone made by AKG, and the comparison is not exactly flattering. Of course, a pair of AKG's "Microphone X" costs about ten times what you're looking at here. And maybe we've come to the root of why it's hard for me to say a lot of nasty things about my Samson CO2s. They are so, so cheap for what you get, namely: a pair of condenser mics, two mini shock-mount/mic clips, two windscreens, and a sturdy, padded plastic carrying case. My griping aside, these things do a borderline-acceptable job as overheads, and in other applications (such as acoustic guitar) they are quite useful. I would probably recommend them to beginning engineers, people on a recession budget, or to anyone looking to keep a couple of budget mics on hand. More serious project studios and home recordists might want to save up for something a little nicer.