Better solution for uncomfortably low bars: a stem riser, or taller stem?
Stem risers do work but have limitations. They increase the amount of force you can put on the headset (as does anything else that gets the handlebars further up), they can break (unlikely but possible), they add a little slop and they often creak (a consequence of the slop). If you're a strong guy with wide handlebars and you're prone to really grunting on the bars you're more likely to break a riser (or anything else), and will probably find the small amount of extra slop makes the bars feel loose (or as though they're about to break).

threadless:  quill: 

I've generally suggested them as an interim solution for someone playing with bike fit, or for someone who wants a bigger frame but can't afford a new bike.

Right now I have a back injury that means I need a more upright riding position, and I've obtained that via a set of upright bars that have a bit of rise as well as the sweep back, and a stem with more rise (that I swapped off my old commuter bike).