I have the GO cutter and am enjoying using it... a lot! I am using it to cut up my scraps into useable shapes for scrap quilts. I have also used it to cut 4 quilts ready for piecing...less than an hour per quilt.
I've mainly invested in shapes that coordinate...squares, rectangles, triangles as well as the tumbler and circles. Watch for them on sale. Also, my GO came with a die that included a square and triangles. Happy cutting!