I think that's the only algo that may make sense to power up AMD rigs - to confess, I have 4 AMD cards on X13 on and off, but solo mining is almost impossible for any coins after may be just a day.  Just think about how many AMD whales in the market. But X13 soon becomes another X11, new coins are launched every week or even on a daily basis.  I bet big on Maru before, but it seems almost dead now, unless someone picked up like SummerCoin V2.

And if you think it different way, those X13 will lure most AMD cards over there, and leave other NVIDIA coins alone...

Well, nothing is too profitable at this point. I even had some 750Tis shut down.