I have driven both, it depends on your preferred trail and use, as to how you are personally going to rate them. For me if I can't run 15mph on a trail without ripping the suspension out from under it, then why do I need a turbo or a machine geared for high speed running? Again it comes down to use, not all machines are for the same use people try to compare them and they are not designed for the same use. If you compare a monkey to a fish and judge the monkey on his ability to swim vs the fish he will lose every time. Same for the fish climbing a tree.
The parts on the KRX are in some cases 200% larger, it has steel fender wells, steel skids, steel is dense and heavy. Add all those beefed up parts to a Talon and it'll be 300lbs heavier. The A-arms I have on my machine weight 186lbs...without ball joints or the larger tiers, needed due to steering angle issues using factory style tierod ends. The 8 factory I think weighed around 30lb which is the same as one of my rear lower arms. Not a desert runner, slow and steady rock crawling. They have ½ UHMW skids on the bottom of the arms. The cheap tires on the Talon are LIGHT, the beadlocks and larger/thicker tires on the KRX are heavy. You will add 300-400lbs REALLY quick adding parts to the talon. I spent a lot of time looking at what I was going to have to do to a TalonR/Talon X4/KRX/MY Pioneer to get it to where I wanted, the weight, AND the cost to do so. Where "I" wanted was going to be $28k/$34k/$23k/@$2k for the 4 machines. The weight was going to be very similar for all except the X4 it was going to be slightly heavier. The Pioneer ended up being heavier because the design of the arms changed between when i pulled the trigger and when they got made, and cost slightly more because we were figuring out somethings as we went. .
I went into the re-build of my Pioneer 1000 trying to shed weight up high and move it down low because we play in the hills, rocks, and off camber trails.
There are several drag races showing they are dang near even acceleration wise and hill climbing. The DCT gives the Talon a short lead off the line but then the KRX holds the gap. The KRX is not the fat cow everyone on the web says it is because they can read a spec sheet. Maybe on a short course the Talon would spank the KRX because of that but most people don't seem to be buying the KRX for racing.
Numbers don't always tell the truth, numbers say the Talon shouldn't out accelerate the NA RZR but it does, numbers don't show torque numbers the Talon has torque vs HP and that gets it moving, it doesn't have the gearing to play in the rocks or thick mud, but its great on the trails and in the desert.
It depends on your definition of fun, some guys love to play in the mud like a pig, some like to play in the rocks, some like to run 100mph across the desert like their hair is on fire. In each one of those categories you have subsets of slow and fast.
I am not trying to sell you on either machine, I like people to have accurate information so THEY can make their own decision. There are several really great members on here that I never ride with simply because we like to play on different playgrounds. We ride the same machine but they are built by us for different uses.