You can spend a lot of money on a fancy CNC machined stem, or you can buy a really well designed, really cheap one like this. The thin four bolt clamp and super light (126g) weight of this tiller might cause doubts considering the price, but we've wrung its neck all through summer and autumn on our race bike and it's been absolutely fine.
It's not the stiffest piece around and there's no oversized option, but it hasn't creaked or snapped and it comes in three different rises (7, 16 and 35 degrees) and 80 or 100mm lengths. You could easily pay twice this much for an inferior stem.