I think Jane from QuirkyBaby reviewed this recently; see her site http://www.quirkybaby.com to get info.
From what I understand, the Performance/Sport line has a bit more width in the shoulders, so it might be better for a broader person. The fabric is supposed to be wick-away, lightweight and do OK in water (i.e. - wading at the beach), so that might be another good selling point for you.
I am considering getting one for my DH for Christmas so we can have two soft-structured carriers for our DD, who does just fine in our regular Ergo. I thought that maybe it would encourage him to wear her, especially since, by Christmas, she'll be big enough for back carries for sure.
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Liz
DD (3/2010)
"Make mistakes! Get messy!" - Miss Frizzle