From what I've seen, there are usually some sort of upgrades when GK does that in thier product line. What the specific differences there are, between the 1001 & 1001 II, I couldnt tell you.
it's also supposedly voiced a little differently, for a slightly warmer sound and more low end... and it's cosmetically different to, if looks matter
I thought it was the mark I that had all the reliability issues. I heard the mark II only had one bad batch.
That's what he was saying. The II has some reliability fixes over the I. Though, to be truthful, my MK I has had NO issues whatsoever. I have broken knobs off accidentally, and fixing it was super easy. Also, GK's customer service was very easy to deal with! One thing, though, the newer GK's control potentiometers have a bracket that you have to solder along with it, which gives it a more stable connection to the circuit board. If you replace a pot on an older one, you have to cut this part off.