I am looking at buying a road bike for training and possibly racing purposes, and have been presented with several options in frame material. Primarily I am interested in titanium and aluminum frames, however I am not sure about the benefits/drawbacks of these materials, and I'm reluctant to take only the salesman's word for it.
I anyone could give me a quick run down of their experiences with these two materials, I would greatly appreciate it. I haven't got any experience with road bikes myself, and thus am not well equipped to make a purchasing decision without more info.

Thanks.
Sly