Stick with ones that [at least claim to] have a 2 micron or thinner ribbon - not 6 micron. If you can solder, you can get a replacement transformer (Lundahl 2912, for instance) and drop it into the mic, and with the new transformer, you'll have a mic (I think) you'll be happy with indefinitely, or until you break it, whichever comes first. If you're going this route, the brand isn't so important, I believe, since the cheap ones are coming off the same few assembly lines anyway.
If, on the other hand, you want the best cheap one without intending to put a new transformer in it, maybe somebody else can help - I've never used a Superlux R102 or any other mic that looks like it, btw.