I'd have to agree. Am drinking it right now, 1 day post roast, in a roasted blend with Sipangan Bolon.
As an SO espresso, it can be a little too much if not left to mature for while first to tame it down a bit.
Geez Borat, I don't know how you like that Sipa - I had a pallet (960kgs) of it earlier in the year and it was not very nice - extremely high in acid prepared for the North American market. Not at all like a Sumatran. Had to dilute in down in some of the lower-end blends and use it sparingly - such was the impact it would have on a blend.
Just on the subject of MM - what amazes me the most is a high percentage of home roasters trying to learn the art of roasting and blending, yet gravitate early in the experience cycle to MM, which can be challenging to work with.
I don't wish to sound negative towards MM, but you could save yourself quite a bit of early heartache by leaving this bean till you understand the basics of blending and the effects of more commonly used varietals.
Of course, if you love the MM, there is no stopping you - and nor should my comments persuade you to stop using it. It's a polarizing bean and requires a good understanding to get the best from it.