My dad just underwent the seed implants. I think he had 88 seeds implanted and it took about 3 hours or so. He was in recovery for about 2 hours and then went home. He was sore for about a week and was almost back to normal after that. The only thing different is he has to urinate more frequently now, mostly due to the medication and the enlarged prostate.
He too was worried about maintaining his sex life and bladder control. He choose this route because after looking at all of the other options, this one seemed to be the best for him.
If I remember correctly he was a 4 on the Gleason scale and is 55 years old. I don't remeber what his PSA level was but may have been close to yours.
One thing to ask your doctor about is the size of your prostate. My dads was enlarged, which is normal with prostate cancer but his doctor would not operate due to it being "larger" than normal. He had to get a shot to help reduce the size of the prostate which lasted 3 months. Luckily the shot did what it was suppose to and the prostate had reduced in size by a third. If it hadn't, he would have had to get another shot and wait 3 to 5 more months before he could start the actual treatment.
I hope this helps.
Nick