This is a very tricky question and I do not think that you will get a correct statistic here since most people that are here have some lingering problems.
Vast majority of patients that didn't have any problems with either RP or RT will tell you that they are very satisfied with their choice - but they are not here to tell you that, or are here in very small number.
"Better" is what is more acceptable for you - dealing with side effects immediately or later IF there are any side effects. Some people have RP and no recurrence and no side effects and they will tell you (if they were here) that they are very happy with their choice and it would also apply for RT patients.
Both methods can have possible (and almost the same) side effects. Some people got incontinence after RT but rarely, but they will mostly deal with possible urethral blockage in couple of years down the road or chronic cystitis, or chronic proctitis, or secondary cancers etc., some have serious side effects from using ADT , like osteoporosis, heart issues, low testosterone levels that might not ever return to normal amount thus having ED and low libido, etc, etc.
At the same time RP can cause permanent incontinence in about 5% ( but percent can be much higher with inexperienced surgeon) and also ED.
Both have pros and cons and unfortunately nobody can try the both ways and see what worked better for THEM. So - it is all about "picking your poison". What looks more "manageable" for you ? It also depends of you age, health status and life expectancy.
Regarding success rate, the only time where RP has little bit more advantage than RT is in the case where pathology shows presence of cribriform or ID formations.
My husband will have RP and he will never regret it, no matter what will side effects be. One can not regret a choice well made, one that you make with certainty and well informed - one that gives you the best chance for survival. Also, he sees surgery as "no big deal", and to him it looks like "one stop service" - chop it out and "finito", (hopefully, knock the wood). For example, to him ADT looks like a torture, especially since it effects cognitive capacity and his whole work is based on creative and inventive processes. He works full time one job and has 2 additional startups on the side. Downtime due to tiredness or "brain fog" is just out of question for him.
Second important factor is that his pathology showed both cribriform and possible IDC , and RP can offer a better result in those cases. He is fully aware that down the road he may need additional treatments if RP does not prove to be curative for him, but again, than he will have no choice. Given a choice (as he has it now), surgery is more appealing to him and will give him possibly a better chance for survivorship.