Those two tractors are nearly identical in specs & features.
1734e/L100 loader:
Machine base weight: 2734 lbs
HST PTO HP: 27.2
Hydraulic output: 10 GPM (6.2 implement)
3pt lift @ 24": 1600 lbs
Loader lift height: 98.6"
Loader lift weight @ full height: 1282 lbs
L3301/LA525 loader:
Machine base weight: 2734/2778 lbs
HST PTO HP: 26.2
Hydraulic output: 10.9 GPM (6.8 implement)
3pt lift @ 24": 1435 lbs
Loader lift height: 94.3"
Loader lift weight @ full height: 1134 lbs
...
So the Massey has a slightly better loader, 1 more HP at the PTO, and lifts a tad more on the 3pt. The machine weights are identical. They both use a treadle style HST pedal, which some people love, and some people hate. Overall, the machines are so, so, so close in every spec that it will come down to how each machine feels to you while using it.
Something else to mention, Massey offers a 5 year warranty, and I think the Kubota warranty is only 3 yrs. There's a lot of value in an extra two years of warranty, in addition to the $2000 you're already saving on the purchase price. Also, Massey usually offers better financing terms than Kubota.
Good luck! Both are good machines!