I've bought items from all over as well. Czech republic, Slovakia, the UK, Ukraine, China, Korea, Japan all in the past year. I just purchased my MZ-3 about 2 months ago from a Japanese seller on the 'Bay - went perfectly. EMS shipping from there is ridiculously fast considering the distance. The seller's English, as you've noted, wasn't the best, but he had loads of feedback and the item looked legit (e.g. not just stock or reused photos). It arrived in perfect condition. Top notch, really.
Again, check the feedback - I'm always leery about purchasing anything from a seller with poor or, even moreso, very little feedback regardless of their location. Come to think of it, in the past year or so my only two negative experiences (which I'll not get into) were both from US sellers, one (to my dismay) which had very good feedback. You never can tell for certain. Just be cautious and ask questions. But yes, overall, there is nothing scary about Japanese sales - just a slight language barrier and a longer wait for items (and a bit more shipping costs).
*You also run a good chance of getting something packed with a Japanese newspaper for packaging/padding which (to me at least) is always kinda fun when you're opening it.