I'm using Deloa's Boomerang, I got it in several sizes. This is the first time I've used curved so I can't say if they are worse or better than anything else.
http://deloasquiltshop.com/
This is the 20" size and it's still not big enough to extend to where the two arcs meet along the edge. That's really why I gave up doing the cross hatching, it wouldn't reach. Especially from the 4-patch between the arcs to the farthest point that each line would need to go on the other side of the arc. I tried over and over and it just wasn't going to work.