Can anyone tell me the advantages/disadvantages of riser bars vs. flat ones? I've always ridden with flat bars with bar ends but recently someone gave me some risers and I wanted to hear different opinions before I install them. Thanks!

More upright vs. less upright, wider vs. narrower, thats about it really.

i would say primarily preference. i will always take risers over flat because of my motorcycle background. for me, it feels like a more neutral wrist angle...but depending on how you hold your arms the same argument could be made for flat straight bars.

100% personal preference. Risers are more upright, as stated before, and generally are considered more "comfortable" (with the same stem). I ride narrow flat bars for racing, my brother rides wide 1" risers in the same races. Each to their own. Try them out and see if you like them... you can always swap the flats back on if you want.

You can achieve the same position with either type, so it's entirely preference as far as that goes. However, flat bar/stem are lighter and stronger compared to riser bar/stem, assuming the same materials/construction.

You can get any sweep and any width you want in nearly any style of bar. As a general rule of thumb with perhaps a handful of exceptions, risers are wider, end of story.

Thanks for your input everyone! I appreciate it. Maybe I'll get out the hacksaw and try half flat, half riser. I'm already half-a**ed. Thanks again!

Also, keep in mind, that flat bars may be quicker steering or more twitchy than risers, due to the fact that they are normally narrower. This is not always the case. Riser bars do put you in a more upright position when using same stem lengths and angles. Your riding style may dictate which bars work better for you. I prefer riser bars for downhill riding as it transfers my weight back. Flat bars tend to put me over the front wheel, which helps climbing abilities.
Bottom Line: personal preferance....Experimentation will lead you to the most comfortable and beneficial choice.