Fair enough but keep in mind that even the 2610 has a lot of stump pulling power in low range and that a properly ballasted tractor is as important as power when considering ground engagement tasks. Most folks don't try to pull out stumps or trees anymore. Using a grapple to rip up roots and pushing trees over is more common. Those tasks are more a function of loader strength (same on 2610 and 4010) and weight which is also the same.
If you must have more horsepower no one will stop you but keep in mind that implements make more of a difference than horsepower for most tasks. Putting the extra money into implements is often smarter than paying the premium for horsepower. Offering 40 hp in this frame size is just a marketing game. Look back at the past twenty years of CUT development and you'll see that 25hp or so in that frame size has been considered decent power. They bore out the engine a tad, slap in bigger pistons and engine software and charge $2000 more. Easy for Kioti to make more money that way but not necessarily the best bang for the buck.
I gotcha. I was also looking at PTO HP. Its a huge jump (in my mind) from the CK2610, rated at 21.5 PTO HP to CK4010 at 33.5 PTO HP, which is about 35% more power. Wouldn't that allow me to run implements more efficiently? I know a 5" rotary mower will be more than enough power, but what about other things? Tiller, wood chipper, stuff like that? It was basically a $1K jump from 2610 to 3510, and then another $1K from 3510 to 4010. The biggest bang for the buck seemed to be the 3510 with its 28 PTO HP, but then my inner Tim Allen "More Power" took over and said for $1K more why not get 5.5 more PTO HP. Also, with the 3510 I already have to be subject to the DPF as well, so no difference there either. I guess basically I am just scared of the 2610 for what I consider an extreme lack of PTO power (though I don't really know if that would be an issue or not). According to the spec sheet, they all have the same pump flow rate of 11.7 gpm, so there is no advantage there.