I am not very familiar with McCormick tractors. For landscaping and debris removal, HST would be very high on my list. That is available with JD but not with the Mccormick CT65U (57hp) which is syncho gear shift. JD has power reverser with with gear shift but no apparent power reverser with Mccormick. I would not want to shift all day. Web says Mccormick non cab is 5400 lbs and JD around 3700 lb. Jd with cab weighs 4345 lbs. Mccormick with cab probably adds 500-600 lbs. Then add 1100 lbs for FEL and the Mcormick will weigh over 7000 lbs. Kind of heavy for landscape tractor and may require more sizeable trailer, especially with attachments.
The 4x20 will be noticably more capable than the 4300. 4320 has 48 hp, next size 4520 has 60 hp. Plenty of power in compact package even if go with HST. Lift capacity for FEL on JD and the ct65 is about the same.
I would guess the Mccormick is cheaper. The Ag and utility tractors are cheaper than the similar Case or JD tractors. In my areas, the Mccormicks are not big sellers talking with dealers. Any newer brand always has some difficulty breaking into the market. Resale may be difficult with a Mccormick.