I have meniscus/cartilage removed from both knees due to football (soccer) and skiing. I continue to play football 3 times a week, and ski almost every day when possible.
When i had one of the mensicus repaired, i was told by the doc that its a 50/50 success rate. There is minimal blood flow to that area, so the healing process is very slow, if it is there at all. I rehabbed and looked after mine for about 3 months. Just as I was starting to jog again, i retore the meniscus whilst crossing the road. fun. I had to go back into surgery to have it removed.
It is definitely better to repair it if they think they can - after all, you dont want to be going around without any shock absorbers in you knee. However, make sure you take your time, as the meniscus is very fragile. If you start too soon, you WILL tear it again. If that happens, you WILL need another operation and they wont be able to repair it again. They will have to trim it - this is not good.
My advice would be to take your time, and very slowly introduce new things. jogging straight, jogging and speeding up then slowing down. then try turning. then try stopping and accelerating. its a really lengthy process. a harder and more delicate rehab process than ligament repairs. i know through experience. with a bit of luck, you should be fine in 4-5 months - just dont be too bummed if it goes again.
If it does, its a quick snip, 3 weeks, and you're good to go loco!