In reply to climbit123:
If you are doing an iron man rather than a normal tri, comfort will be very important, so bike fit is probably what matters most.
In your position assuming you don't have any other bikes, I would go with the road bike with clip on bars as it will be much more confortable to train on, without a significant penalty (also in that price range you are loking at fairly ordinary TT bikes)
Have a look in the second hand market as you will get more for your money