I really only use the D config for the Summoner, as far as canon goes - the rest of them are just too under-ammo'd for my tastes. Still, a lot of that probably has to do with the kind of maps I take the Summoners on and my playstyle.
There are some alternatives without going into customs, though - the Stooping Hawk and Septicemia. Yes they're mediums, but their speed is the same and their armor is only about 10 points less. They both have jumping configs, and imo most of their configs carry more reliable firepower than the majority of the Summoner's. Both are still present in the Homeworlds after the Reavings, too.