I dont know enough about components to say about a difference - maybe it doesnt have any difference on lower power circuits.
I had a read on some sites, including here, and some say its good and some say it's not , with respect to tone. Someone on ( cant remember where ) said bits fell off his Stinger, and another said he wired his in, then immediately took it out again.
The East MMSR is not a direct copy , as stated by John himself , but he uses good quality components, and his pre's are exceptional in build quality. Hence the higher price.
I guess i'm leaning more towards John's pre - i've had a few of his in the past and they're the canine's cobblers.
I dont know what's out there apart from the Stinger and John's MMSR - so it may be that i've only got 2 choices