They're pretty damn loud but the sound is awesome. Honestly, I think they're one of the better looking exhausts available for our bikes. The pix you see online dont do them justice. I have a set of the Ti Apex slip-ons with the carbon end cap and the angular cannister design works very well with the lines of the bike. I also removed the FMF logos since they are just a foil sticker. The things that sold me on the FMF's were their length and lack of a hanger strap wrapped around the cannister. They come with a tab welded to the back of the cannister body that cant be seen once they're mounted. It hangs them from the end of the sub-frame, exactly where the stock cans are mounted. As for the length, it seems like everyone else's designs stick out way too far in the back. The FMF's are just a little longer than stock. Overall, I think it looks very clean. Several people have commented how they look very "factory".
Installation was also simple and straight forward. I had no problems getting the pipes fitted and all the joints fit snugly together.
However, I will warn any potential buyers to purchase them at your own risk. My right side cannister was not sealed correctly from the factory and developed a leak within 3 days. When I contacted the FMF warranty department they refused to replace the cannister. Instead they made me send it to them, which obviously disabled my bike. To me this is unacceptable. If you purchase something for $1000 and there is a defect in the product, the manufacturer should replace it no questions asked. The best deal I was able to work out with them was a pre-paid ground shipping label and next day turn around. Since I live in Vegas and their facility is in the LA area that meant I had my pipes back in 3 days. However if someone who lives on the east coast had to go through this, they would be looking at 2-3 weeks before getting their parts back.
So, yes, I do like my FMF's but would I buy another set? Probably not.