My Can-Am 800XT Camo is the fastest and most powerful out there. It has the best suspension (no camber or wheel scrub) by far.

 

I've seen a lot of people have some major issues with Yamaha quads, and some not so major issues that are just annoying. My KFX 400 has got to be the best quad ever built. That thing is unstoppable, not the fastest by any means, but it'll damn sure keep goin and goin. Like the energizer bunny.

 

Speaking strictly motocross here, I don't think you can go wrong with any of the four Japenese brands in the 250 four stroke class.
We currently race an 06 Honda CRF250 and an 07 Suzuki RMZ250. Both are great machines, just wish they were easier to start after you drop them! (the Honda can be a little finicky).
I don't have much experience with the KTMs, they are great looking machines but a bit pricey.

 

For dirtbikes and Quads Kawasaki all the way.

My first bike was a Honda XR-75 tho.

 

The 2007 KTM's have no kick start. That is pretty dumb in my opinion. But for reliability, suspension and starting, they are the best.
I challenge anyone if you are looking for a quad to look at the can-am and compare it to ANY quad out there before you buy anything else. the material and workmanship is by far the best. The 400 Outlander will be above par with any of the big 4, but the 650 and 800 outlanders are far superior.

 

kawi for the quad because i love my brute for and i would say honda for the streetbike. ktm for the dirt bike

 

Kawi all the way....I have a 06 brute force 750 with HL lift springs, 29.5" outlaws, HL ICM power pak, HL extreme clutch kit, Kingston kustomz relocated radiator and kingston kustomz snorkle's

The Can-am 800 is a nice quad but with the rigt rider and brute can lay a whoopin on it I know cause mine did.

 

I cartwheeled my 800EFI across a frozen soybean field at about 40mph, then rode it another 3 1/2 hours....in 2WD. Found out the 4WD engagement runs through the digital cluster and when that's in approximately 4,536 pieces over a 150ft swath of ground, the front wheels don't dig anymore.

The fact that it rides good, pulls good, goes good, tolerates my aggressive style (I out jumped a Predator Troy Lee and a KFX 450 with it...the landing was bad, more broken parts) and is still going strong says a lot IMHO.

I wasn't a huge Popo fan when I bought it, but it's made me a believer.

 

I just picked up a Polaris Sportman X2 700 EFI a couple weeks ago. So far, it's been money well spent.

 

I am going to say Kawi all the way mainly because I am sponsored by them for dirt bikes and they make a really good dirt bike. I was at Yammy before that and they make good bikes just didnt have the power (or the contract agreement) that i wanted. So i switched. I also have a Can Am Outlander 800 and I figgen love that wheeler. It goes anywhere anytime anyway that it can and as fast as you wanna go. I out rode a Honda sport quad cause the Can Am (IMO) handles better and has more power.