They say that success rates for all kinds of medical procedures
have a lot to do with how much experience the practitioners have.
So one important question is, how many prostate cancers are being
treated per week at each center?

Another question that I would ask myself is, how comfortable am
I with the staff at each place.  Sometimes you meet a doctor and
everything clicks.  He or she is careful, attentive, works slowly and
precisely, listens when you talk, encourages you to ask questions,
and answers them knowledgeably and intelligently.  Other times you
meet a doctor who is abrupt, arrogant, thinks he knows what is
best for you without listening to your opinion, and wants to get you
out of his office quickly so he can get on to the next patient.

I might be wrong but, personally, those differences mean more
to me than the reputation of the doctor or the clinic.

As for age of the equipment - I don't know.  However I would ask
for specifics of the proposed treatment at each place - machine type,
radiation type (3D, IMRT, or something else), number of grays, and
target area.  Then ask people here about them, or ask the other
clinic about their competitor's prescription.

Good luck.

   Alan