I think I am for this as Jacoby is a break away threat, reduced his drops/fumbles and matured over the years, and contract is reasonable given similar player salaries.
I did find these stats for WR in 2010
http://www.footballoutsiders.com/stats/wr
Jacoby catch/play to him success rate is 65% which appears pretty high.
For instance Santonio Homes is considered a top FA WR , his completion percent was only 54%. T.O was 52%, Randy Moss 44%, Larry Fitzgerald 52%
Of course stats are stats, who was competition, who was QB, what was the play call all enter into these stats, but Jacoby looks ok.