The only drawback that I now have found is that in sand if you get throttle happy they will dig trenches other then that aces--for the money and performance they give me in all the other areas I'd still buy them again

Any body got pictures? I have a 500HO am going to put swamp lites on it from stock on it now. I just want to know if I should go to the 26" or stay with 25". Do the 25s make it look bad to the bone and do the 26" cause issues that require extra upgrades?

My first 350 Grizzly had 26x9-12 front 6ply Maxxis Zilla and 26x11-12 with the aggressive 1.19" lug and handled them no problem without any noticeable power loss so your 500H.O better.
No up grade was needed just a tire change and go, of course Zillas are the lightest 6ply mud tires made.
compare for yourself on this site
ATV Mud Tires : Best ATV Tires

Narrower Swamp lite 26x10-12 with a shorter 1.12 lug is 27lbs Interco Swamp Lite

The wider Zilla 26x11-12 with a taller 1.19 lug weight 23.3lbs Maxxis Zilla

Even the much larger and wider Zilla 28x12-12 weigh only 27.5lbs if you scroll down the above link.

Larger tires do not cause power loss it's heavier weight that does so just keep a eye on that when choosing tires.

Some years the stock tires on a Sportsman 500 were 26" so there's no problem going from 25" to 26" as long as they aren't too wide.

My plan is to go 1" wider.... that's going to 9 in front and 11 in back. Not looking for any clutch problems at this time.

Extremely if used on pavement, I purchased a pair for my 500 scrammy and month later the fronts were almost worn right off.
Keep in mind tho I did a lot of pavement riding probly once a night at least.. Other then that great tire! Just don't use on the pavement if u want durability..
Hope this helps