the teebird is a great disc. the reason being is because it is so straight with little fade at the end. there are not many discs like this; most have inherent "s" shaped flights of some sort whereas if you turn a teebird it's more angular and forward. a very "flattened" or drawn-out "s" if you will.
if you don't throw far, get a dx as it will be straightest overall.
if you have some power, the gstar will be. it's hard for me to find dx teebirds that have no flip out of the box so i keep them for hyzerflips and beat them into turnover discs; i throw my dx teebirds up to 400', sometimes a little more if there's tailwind, in the open field for max D. not golf lines. they go faaaaaar.
the gstar can really take some heat on a flat rip and hold the line with next to zero fade. they are the straightest for me out of the box, maxing at 450' with my distance drivers and about 400' with the gstar teebird.
if you want straight to reliable fade, the champ is very good. if you have a cannon i'd be willing to bet the champ or star is straightest. i have never thrown star but the champ is what i throw when i want a flex shot or zero turn no matter what; decent windfighter. these are not straight for me; rather they are moderately OS.
weight doesn't become a significant factor until you go sub 167 IMO. PLH rules all. if you want the most windfighting ability, get max weight. i usually only bother going max with my windfighters, and even then i don't really care.