Few more spec's for you to consider. Going off MSRP, the Yamaha is $500 more from what I saw, but thats not your out the door, you can get them much better deals. Mine was out of the crate for 1200 less than MSRP from a dealer - not 1 fee, just tax.
Suzuki vs Yamaha side by side
493cc vs 558cc
2 disc and sealed oil bath rear brake vs 4 disc on the Yamaha
The Suzuki is 1'' wider in wheelbase and general width
The Suzuki is about 3'' longer
The Suzuki is just over 2'' higher
Suzuki is 60lbs heavier at 661 lbs. (Suzuki dry is 661, Yamaha wet is 648). Suzuki is over 700 easy with fluids. That is a heavy machine for 493cc.
Suzuki is 6.7 travel in front, 7.7 rear, 11' of ground clearance
Yamaha is 7.1 and 9.5 travel, and 11.8 ground clearance and its adjustable 5 ways, Suzuki is not.
Yamaha hold almost a gallon more of gas. Suzuki being a heavier machine might burn more gas and it holds less, so consider that or bring gas with you.
Overall, the Suzuki is a larger, heavier machine with less power, travel, and clearance.
Also remember the design of a Grizzly, fuel tank is centrally located under the seat, so its more stable, lighter, and still has more clearance everywhere...That is HUGE with ATV's. Imagine on a trail which machine is more user friendly and safe.
Lastly, from what I read is the fuel light and such on a Grizzly is digital with a warning light, on a Suzuki, its a little gauge. (not that accurate).
King Quad 500 AXi
2009/2010 Yamaha Griz 550 EPS
ATV.com Side by side of Yamaha vs Suzuki