G-K MB210 vs. MB210-MkII vs. MB500 questions
 

Ok, I've searched, I really have, but I'm trying to find concise info on the differences and similarities between the original metal grilled MB210 and the cloth grilled MB210-MkII. I've found a good deal on a new MB210, but want to make sure I wouldn't be missing out on something that only comes in the MkII.
So far I've found that the original MB210 may be made in China or the US (how can you tell? I want a US made one) and I can see a small fan on the MkII. Any other changes I should know about? Same 10" drivers? Same cabinet bracing & damping issues?
It's not as affordable for me, but I'd kind of prefer some of the features of the MB500 and a separate head/cabinet over a combo. Does the MB210 MkII use the same power amp section MB500? With the MB500, can you feed an external signal into the effects return without cutting out the bass signal? It's not a deal breaker, but it'd be convenient if I could do that.

The mkII Has the new chain output to control GK's line of powered extension cabs. I'm not sure if anything else has changed or remained the same as the metal grilled 210.

they also rotated the Direct Out xlr jack. not a huge deal, but if you had an original MB series combo, if you ran the direct out, it was nigh-on impossible to get the dang xlr connector out of the amp without using a key or knife blade or something. it looks like it's been addressed in the Mk-II

If you want an easily accessible matching extension cab for it then go with the new model.

The MB210 Mk i or II uses the same power amp as the MB 500. G-K effects returns interrupt the signal from the preamp to power amp (serial effects loops). Effects send will not interrupt.