Well, the body shape of the standard is a little different, with the 22 frets, they hang differently on the body. I know this is obvious. But it was a factor for me. The standards have more neck choices as far as shape. The standards I had were wider at the nut, like an Ibanez Jem. I'm not use to that, so it was a little uncomfortable. I have a Modern with a basswood body, so it's available. Alder, Koa, Maple, Korina, all available.
Honestly, the choice for me was just what fit me. I would have liked the Modern more at first as a 22 fret guitar, because that's all I had played for years. But I have come to like the 24, though deep down I am more comfortable on a 22. But I'm not sure how that would have effected how it fits me.
The standard, depending on the neck carve is just as much of a shredder. I'm sure many prefer the wider, and thinner necks that are available. But there are many neck shapes, and they can get pretty chunky too.
For what you are asking, I think Suhrs are all quality, so it is just a matter of deciding which neck you like more.
