Properly designed I don't think one form of suspension is better than the other.

As far as valves, I prefer a screw type adjuster. With shims, you have to have a variety of replacement shims so if the valve gap needs changing you can pick the appropriate shim.

If you are going to have service done at the dealership, it wouldn't matter anyway.


Edit: Now that you've got it narrowed down to a short list, have you been able to test ride any of them?

 

Yes I've taken test rides on the Sportsman 500 HO and the Grizzly 450, along with a test ride on an older grizzly 660. I prefer the physical size of the Polaris since I'm a bigger guy but I prefer the ride of the Grizzly. The Polaris felt too spongy and soft. The grizz felt more nimble.

I'm really wanting to ride a KQ. Either the 450axi or the 500axi. They are physically larger than the GRizz 450 and more in similar in size to the SP500. Although I think the 500axi will be out of my price range. My local Suzuki dealer has a building right downtown so there really isn't a place to test ride them. My preferred dealer however does have a place to test ride but they are located 1.5 hours away and I havne't been able to make the trip there to test ride one.

 

I've only ridden the 700 KQ briefly. I felt the suspension was pretty well balanced, but I have a personal preference for more feel and feedback and less body lean, as opposed to a softer, mushier suspension.

Really these days most everything on the market should be pretty reliable.

 

Get the 500 H.O out of those, read this 4x4 ATVs Comparison Test Report 4x4 ATVs Comparison Test Report - What's the Best 500 Utility ATV? can,t believe the 450 Grizzly cost so much,its a smaller (Chassis wise) and less powerful (Motor wise) ATV.

Here another one if you think they where wrong. http://www.powersportsnetwork.com/en...ew.asp?code=85
They can,t all be wrong. You may see a 500 Rubicon or 500 Foreman get compared with a H.O but never a Rancher.

I like the 450 KQ but not for $1300 more.

As for the Rancher 420 it did not do that well even in this "Which 2009 Budget 4x4 ATV is Best?" report. ATV Comparison - 2009 Budget 4x4 ATVs Reviewed.
Unless it cost alot less then the rest. The Rancher 420 is even smaller then the 450 Grizzly (421cc really) with its small 24" wheels.

 

Those MSRP's aren't really indicitive of what price I can get them for. Here are my real world price options:

'11 GRizzly 450 = $5895
'11 GRizzly 550 FI = $6595
'10 Kingquad 450AXI = $6295
'08 Kingquad 450AXI = $5695
'11 Kingquad 500AXI = $7195
'10 Sportsman 500HO = $5300

I think based on all the reviews I'm leaning on the '08 KQ for $5695. The Sportsman tested in your article was an EFI, not an HO. Maybe I'll stretch the budget and get a Grizz 550. Who knows.

 

Out of those, I may go for the 2008 450 King Quad, I only care about condition not Year. When I bought my 2001 used three years ago It was because it was in mint shape vs some 2004s and 05 that where in good shape.

There really no real world difference between the H.O and EFI, I rode a few 500 EFI,only the sticker on the side told me it had EFI not any performance improvement, but the EFI 500 come with larger 26" tires I think.

That Power steering is one costly option. You can get Big bore ATVs without PS for the price of Mid Bores with PS. Thats just crazy to me at least.

 

Here is a list of Yamaha Grizz 450'S much cheaper than anything you have listed. That Grizz 450 you do have listed is a 2011 with power steering which none of the others have. As I have said before the price debate on Power Steering can be argued but the only people that knock it are the ones who dont have it!!!!!
List of Yamaha Grizzly 450 ATVs for sale

 

In every review the 450 Grizzly is knock for its weak on power 421cc (27 HP) motor. It does not matter if it has power steering and a golden plated gas tank and built in stereo,there no getting around the 421's power issue. Which is not a big deal but the 450 Grizzly should not cost more than the larger Full size,450KQ or 500H.O which make much more power (35hp) also.

I felt bad for the 450 Grizzly being in 500 shootouts but at the time it is all Yamaha had,but now with the full size 550 Grizzly things will change.
The 450 Grizzly should be duking it out with the 420 rancher in some shootout somewhere not with the big boys.

 

You worry bout power I worry bout longevity and overall performance! That 35Hp wont take you any faster on a tight trail than a 29hp will and what about power to weight ratio which the Grizz does win over a Sportsman!

 

look at my group pics ,I rode and ride with a 450 grizzly many times ,yes its lighter it better be its smaller, but it also is much slower acceration and top end. Every 500 Comparison its in its the lightest ATV,but aslo the slowest and least powerful (In feeling). Nothing wrong with not having alot of power or size ,just do price it like it has it is all I,m saying.

Its closer matched with a 400KQ/Eiger ,rancher or even a 350 Briun/Grizzly . there all lighter ATVs than 500s and are slower with less power.

If I had a 150lb Passenger on the back I could still blow by a 450 Grizzly. Where does its power to weight advantage ever show its face?

Here the two reviews comments on the 450.

There factoring its light weight.

.