rehashing the filtering of wort

I've read the pros and cons of filtering wort, but with my own experiance with a basic brown ale when I filter the ferment takes around 7 days and when I don't it only takes 3 to 4 days. What's up with that? What do you do? How do you do it and why?

If you filter wort before going into the primary, the yeast are loosing out on a lot of the proteins that coagulated during the boil and cooling process.

so witch is better a quick fermentation or a slow one or dose it even matter?

Not sure it matters. I know you want a fast start of fermentation. I don't think you gain benefit from fast or slow fermentation though. Just make sure the yeast are healthy

As long as the yeast is healthy (not stressed by too low a pitching rate, high temps, low temps, etc) it doesn't matter. It takes however long it takes. Sometimes a fast and furious ferment is the result of high temperatures and that's an issue. Yeast do love warmer temperatures, but it can cause off-flavors in the beer. If the temperature was in the desired range, though, and the correct amount of yeast was pitched, it's all fine.

I've had a beer in primary for about 2 1/2 or three weeks now. I assume it's done and been done for a while but whether it took 2 days or 2 weeks, I have no idea. I'll check the SG before I go to rack it to make sure it's finished, but otherwise I haven't even looked at it.