Math PhD adviser - The easy choice or the more unconventional choice
You want the advisor who best fits your needs as a student. This is some combination of research area, advising style, career connections, funding, and interpersonal chemistry, but--and this is the big but--only you are in a position to know exactly what that combination is. 

From your description it sounds like T is the frontrunner, but a few hours prepping for quals isn't that much data. Ask T if he is accepting students (or find this out from his current students) and do a reading course to see how it goes.