I'll go out for this one. Being a dobro player, all the shots miss...[
I used to have an Epiphone MB-200. Good starter unit. Is it a Gibson? Absolutely not. In fact, all the pot metal units coming from the Chinese buffet of banjos are pretty much one in the same. Whether it says Washburn, Savannah (Johnson), Epiphone, whatever, it's peas in a pod. That said, what really makes or breaks these things is the setup. I've been playing banjo for over 25 years now (and yeah, it takes a strong man to admit that) and most of the time, if a banjo sucks, it's not setup properly. I've played some pretty high dollar units that weren't much better than a canoe paddle.
Unfortunately it is really hard to find a banjo guy who knows his stuff. Good luck with the hunt!...as for the MB-200 witht he corrosion, a light 3M plastic scrub pad will take that off. Just remember to lightly oil the fingerboard after.
Oh and definitely avoid the starter kits. Yes, sometimes you can go too cheap. Those are junk at the best of times. As a side note, check out the Recording King banjos if you have a chance...they're awesome. This being a Washburn site, I've also played some really hot Washburn banjos (and mandos) and no, they don't get enough credit. Yes the Gibson crowd does poo-pooh them but believe me, it's pure out and out snobbery.