I stuck with the 13" Pro instead of getting an 11" Air.
I couldn't take the squint-inducing high pixel density of the Air. The 13" Pro is the perfect pixel density for me for a laptop. However, I did put an SSD in my 13" MBP.
That may change if OS X becomes resolution-independent, but Lion isn't.
Did the SSD really improve performance on the Pro? Which brand and model drive did you go with?