Brocks / Hindle

They know what their doing, power, weight, quality. Gets loud when you get it. Priced right too.
Go to the manufacturers web sites. Most post data on their pipes. I've been shocked at the yosh site.
I've read TONS and TONS of bike mag pipe comparo's over the years, and all the full systems put out within a couple of hp of each other, including Brocks. The biggest difference is where the power comes on at. Like somebody else mentioned above, the power difference is marginal. Although Brock fans would like you to believe you can get 30 hp with just his pipe

He makes great pipes, but its good to be real

There's only so much you can do with pipe diameter, stepped headers etc, and all the companies know how to do those things...its just about where they want the power to be. Get what you like the looks and sound of, and you'll be plenty happy with the performance.
I've owned Muzzy and Yoshi, and rode Brocks and Akro equipped bikes, all were great, just different sounds and types of power delivery

They all took away low end for more peak power, but the Yoshi took the least away, while still giving a similiar top end hit. More power is nice, but I LOVE the low end pull of my busa, use it all the time, and didn't want to give too much up

I'm not into spinning my big motor way up constantly for good pull, defeats the whole purpose of having 1300cc's of engine

Although I DEFINATELY enjoy a high rpm run through the gears at least once a ride lol.
If I wanted a high rpm screamer though I'd own a liter bike
That brings me to another thought, I've noticed the gen1's stock have massive low end, but seem to rev out slower as they wind up. A full system gives them a lot quicker revving as they wind up, but depending on the system can kill quite a bit of the low end. The gen2 didn't seem quite as punchy down low, but picked up revs noticeably quicker. The age old question, do you want low end torque or high rpm power. Variable valve timing was suppose to fix that, but from what I've heard it hasn't quite lived up to that hype on bikes so far. I wish they'd give it a REAL shot on a bigger sportbike like a 1000 or busa/14.