The ESP Guitar Company

Can you play it in person before you consider buying it? If not, maybe buying it isn't a good idea. That being said, I've bought a few LTDs online and had no problem with them beyond just adjusting the action and maybe a little cleaning. Being manufactured in China doesn't really make any difference over the Indonesia and Vietnam plants- there really isn't that much a difference in build quality. Sure, the Korean plant does a great job, but they also come at a higher price. ESP also stated that they were shifting some of the models from the Korean plant over to the others as they stated the build quality for the others is the same now. If it were me, I'd wanna play it first, get hand's on. But if I absolutely wanted it and the price was good, I'd probably buy it online.

I don't really know too much about either, but they seem to be on-par with each other unless you plan on swapping out the pickups on the M-330R. I think the main difference relies in the set-through neck and the bolt-on. You will get different tones and sustain between them but that's about it. I have both with bolt-on LTDs and set-through necks of the E-II and original Horizon series. There's subtle tonal differences between them and more so when different pickups come into play. None of them are 'better' than the others, it's just about the tone you're looking for. There's pros and cons for each but that's what makes them awesome.  

If you don't like that many things about the guitar, why would you be considering it?

That's really not much of an upgrade.

If you're doing fine with the MH you already have, save for a bit longer and get to the 400 or 1000 level guitar. You'll notice a bigger difference, then.