I do agree that it is a much better grinder! I probably should have added that, lol.
Thing is i dont care much at all for grinds. Like i mostly finger-grind once in a while to test a yoyo’s smoothness, and thats it.
And i guess this is subjective. I like the Sleipnir better 
My preference goes towards the Sleipnir. I find it does everything just that tiny bit better than the MVP and, probably more importantly, I find the shape to be a lot more comfortable. Having said that, there isn’t really anything the Sleipnir does that the MVP can’t do. So end of the day, just pick whichever you think looks better. If I can’t decide between two throws, I usually just pick the one that has a nicer looking colourway (and get the other one shortly after…).
And while we’re on the topic, the Irony JP is an absolutely phenomenal throw. Even more so when you take its price into consideration.
Yuki
I can second what you said about the unscrewing of YYR yoyos. I owned a messiah and unscrewed it more times than I can count and every time I screwed it back together, it was as smooth and quiet as it was when I got it.