I just got mine regassed, the guy said that the std ones are actually very good compared to what is made nowadays. Ours have 1/2inch chrome plated shafts, metal brackets at each end etc instead of 8mm shafts and plastic brackets.... So he recommended I regas rather than change them and he does both so I guess unbiased....
cost me $99 for the regas, which amused me as I put bonnet strus in for $75 (a whole pair of struts is cheaper than asquirt of gas and some labour)
search for strut regas in google and you'll find people or pm me for this guys number, he comes to you and it's done in less than an hour. Mine are fricken awesome now, the tailgate used to fall on me whenever it was really cold....