a2psyklnut

I would only recommend a Tri-specific bicycle to a person who competes on a regular basis, say 10 races per year, and can afford two bikes. A regular road bike for training, and a tri-specific for "race day".

A Tri-specific bike isn't as comfortable as a regular road bike, so unless you have two bikes, it makes more sense (to me anyways) to get a regular road bike and make some modifications to it on raceday.

A regular road bike is much more comfortable for long sustained rides used for training. The slacker geometries on a standard road bike help absorb (minimize) some of the road vibrations. They also allow for a more stable handling bike.

A Tri-specific bike has one purpose. To be as aerodynamic and fast as possible during a race. The forward position helps save the legs for the run and creates better aerodynamics. Aero tubing, Disc wheels, Deep Dish rims, 650cm wheels. All lend themselves to one thing, going faster. The compromise is comfort.

You can modify a regular road bike as follows and is what I would recommend for those who compete, but only have one bike.

Aero bars (of course), a forward seatpost, and a double water bottle carrier for the seat.

I've never understood the 650 vs 700 wheel size debate. Quicker acceration? If so, then all criterium racers would want 650 wheels. Plus, how often do you accelerate on most tri road sections. Usually at the beginning, and then at the turnaround point. I would think a bigger wheel is preferred for sustaining speed once rolling. A smaller wheel makes sense for smaller riders, but that's about it IMO.