I'm looking at new bikes and I'm looking for IRS, diff lock, and at least 500cc or larger also want more ground clearance than I"ve got on my honda rubicon I've looked at yamaha grizzly 660 and the king quad.
I ride mainly trails a few hills and sometimes play in mud.

 

You can't go wrong with either the Grizz or the King Quad.

 

But which one what's the pros and cons of each

 

The King Quad is most likely superior to the Grizzly since it's a newer design. I considered a King quad before I bought my Grizz but decided against it because they were experiencing transmission troubles in reverse when I was looking at them. Suzuki, at the time, wasn't acknowledging any issues when these problems were reported which made me steer clear and buy the Grizzly.

Each has similar features but the King handles better and has more power. You should also consider the new Grizzly 700. I would choose it over any of the other 2.

 

Why not Polaris........sportsman 500.....EFI,or carb.......Has it all IRS.11 inch ground clearance.....proven motor.....great ride......Bright lights (3 in total)....lots of storage with the front rack....2005-2006. Check them out.......caper.....

 

I would buy a Grizzly over a King quad. Nothing against KQ, i just think Grizz is a better buy

 

Did they ever straighten out the EFI problems I've heard about with the Polaris SP 500?

 

not that I know of. I had an 06 SP500efi for 2 mths and traded for an older 700 with a CARB. EFI is not meant to be on an ATV. At least not for my style of riding where Im in mud and water all the time. The carb performs flawlessly where the EFI would fry sensors. (6warranty jobs on it in 2 mths). Anyways. If you go Grizzly, id stick to an 06 660 before being the guinea pig on the 700. Buddy of mine owns a yammy shop and although there was hype and on paper its a mean machine, he says nothing but recalls and nothing but customer complaints on them so far. Until they iron it all out, id wait at least a year. Also, in my experience, its another efi machine which turns me off.

KG is a good all around machine, the 06 grizzly has been around for it seems like forever but is small and tippie and in my opinion, not fun to drive for long. If your a big guy, the poalris would be a good fit (get a carb and not efi if you can). Awesome ride comfort, tons of power, ground clearence. Ive owned a grizz, couple polaris', and bomb. For the long trail riding days, nothing beats the ride of a polaris and outside the new efi, never had any issues with my popo's. if your stuck on KG or grizz, flip a coin, both will do you well. Sit on them and which ever fits you best, go with it.