I went into the shop intending to buy the grizz, but left with the Kodiak.
Reasons I went with the Kodiak:
1) Feel - I just preferred the slightly narrower feel of the Kodiak. "feels smaller than it is" in a good way. The Grizz felt a bit wider, taller, and sporter. YMMV as I'd love to get a Grizz someday for trail fun.
2) Gearing - The Kodiak gearing is geared towards work/torque. I use it for hauling kids around, hauling wood, pulling a trailer, hauling dead critters out of the woods etc... I don't need sportier performance, it's been quite enough I can still hit mid 60s on a windy day.
3) Price - With EPS and front locking dif, the Kodiak was still ~$1500-$2000 cheaper.
There's a lot of carrier over between the two models. Motor and I think the tranny are same, just different weighted gears. Furniture is different and brakes are different.
I recommend go sitting on them and driving them around if you can. We love our Kodiak