My only comment is that riser bars generally have more of a sweep(backward curve) to them than flat bars. Also, risers tend to be wider.
I prefer risers for both those reasons. I'm a big guy, and the wider bars give me a bit more "openess" and the sweep keeps my hands in a more ergonomic position. With flat bars I always felt cramped and my wrists were kept in a funny angle.
Kinda like the difference between a standard keyboard and a ergo keyboard for your computer.
L8R
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