Hi,
I have had the 5 day version of RT.
I had a starting PSA of 17, and a T2b/c diagnosis. I had opted for RT as the primary treatment. ( The uncertainty around the T2b/c edge conditions was one- but not the only- factor in choosing RT). It would have been the standard 20 day job, but the local radio team was unable to get a consistently clean shot at the target, so I switched (privately) to the Top Gun, 5 day, MRI guided machine.
The treatment was a breeze. There were only a couple of days afterwards when I didn't stray too far from a loo . But that was it. The advantages are those you would expect: significantly shorter treatment, and the prospect of a more accurate hit.
Has it worked? All you can ever say is : so far so good. I am just over 3 years post treatment, with a still negligible PSA, so it's : so far so good. Would I do it again? Yes.
Best of luck with whatever you decide to do