I bought this the last time it was offered, mostly because I absolutely love sewing and quilting notions. I like this primarily because of the cut-out that accommodates a walking foot.
But if what you really want is a gauge to guarantee a scant quarter-inch seam for piecing, I'd recommend the Perfect Piecing Seam Guide made by Perkins Dry Goods, which costs around $6 or $7 and works really, really well!