I have the GO. I have the strip cutter and the GO comes with the value die. The only dies I have purchased are triangle dies The value die has the 2" (finished) triangle. I purchased the 3", 4" and 6" triangle dies. I think it is a lot faster and easier to do HST using the dies. They have the corners trimmed so I don't have ears to cut after sewing them. I also have a 4" quarter square cut die. It is great for flying geese along with the 2" triangles for the wings. I agree with some of the others about the strip cutter. It seems just as easy to cut strips with the rotary cutter so I don't use it as much as I should. And it is a lot more expensive to buy. I don't do much applique so I haven't bought any of the other shapes. If I am doing a quilt with a lot of triangles, it is much faster to cut them with the go and the sewing is faster too. No more drawing lines on squares.
Pat