First off, sorry buddy, to hear the news and see you here having to ask such a question. I'm 53, most recent psa 3.76 gleason 6, 3 of 12 cores cancerous.
The general "rule of thumb" is that there isn't any one "best" procedure, because the treatment needs to address your specific situation. For example, if an individual were found to have extracapsular extension, or suspicious spots somewhere else in their body, then some of the treatments which focus on the prostate alone would not probably be appropriate.
For those of us whose cancer appears to have be caught while it is still contained within the prostatic capsule, the general consensus is that either the brachytherapy seeds or a prostate surgery are good options. On this board, however, there seem to be a fairly large number of people who have elected to go with the da vinci robotic surgery. This is what I have chosen to do. This technique is new enough that it is not as widely known as the brachy and other forms of surgery, but the results, when the surgery is performed by an experienced practitioner, appear to be much more encouraging, with shorter recovery times, shorter duration of incontinence and quicker recovery of erectile function.
It has been said (and I agree with this) that the treatment option selected is less important than the skill of the practitioner in carrying it out. Case in point--Memorial Sloan Kettering is one of the top, if not The top, cancer treatment hospitals in the world. They get world-class results from the brachytherapy, as well as the option surgical procedure. They are now also doing the da vinci robotic surgery.
When choosing ANY treatment plan it is important to find a doctor who has performed 500+ of the treatments (this is my opinion), who does them often. Say, 3-4 a week. The top da vinci surgeons appear to be doing six or more surgeries a week, sometimes two or three a day.
I'm not trying to sell you on da vinci, it is just what I have researched the most, lately. Previously I was really planning on the seeds.
Whatever your choice, may God bless you and renew your strength and vitality and bring a speedy recovery.