The aerobars typical of tri bikes add some instability when cornering compared to standard drop bars. However, for the most part, it doesn't matter what bike you are riding; turning is fairly universal.
When cornering, lean your bike, not your body, into the turn. This way, if you over steer, you can bring the bike back. If you lean into a turn with your body, it is much harder to bring your body back upright with gravity pulling it down.
Also, place pressure on the pedal by the foot that is on the outside of the turn. This will help you maintain stability. If you notice accomplished cyclists, their inside leg is bent while the outside leg is pressing on the pedal. For example, if you are making a left hand turn, the right foot should be straighter and placing pressure on that pedal.
Cornering in triathlons is a minimal part of the bike segment. Base your selection on what your A races will be in the future. Will they be flat or hilly races? Also, do you train more in the hills or the flats? This is where comfort plays a role in your bike selection.
Wes Hobson has competed in more than 220 triathlons, from sprint-to Ironman-distance. He garnered 35 first places, 60 top-three finishes and 96 top-five finishes during his 12-year professional career that also included being selected "Triathlete of the Year" by the USOC. Hobson co-authored Swim, Bike, Run and created three triathlon and cycling related films. He coaches multisport and single-sport athletes, organizes triathlon camps and can be reached at www.weshobsonperformance.com or email@example.com.