I recently changed from a Beta 300 2T to a Beta 300 4T and really like the change. It took me a while to get used to it but it takes me time to get used to any new bike. My riding skills are probably average. At my level it is still about doing things with throttle more than clutch. The 4t is slightly heavier but I can't say that it affects anything. The 4t has more engine braking but I can't say that it is a pro or a con. Mine is a 2016 and I bought the oil pump upgrade that is said to reduce engine braking but after getting used to it, I think I actually like the engine braking so have not installed.
It is very very quiet
The 4t has more off idle power in that initial blip. This is good in coming right up to a large log.
The 4t has less power at higher revs so you can be less precise with the throttle. It feels kind of fluffy. The 2t 300 produced a lot of power once wound up which could get away from you and was really no use to an average rider like me anyway.
The 4t power comes on softer, more like a push than a hit. I find it less tiring to ride and it beats me up less so I am riding more. I think everything happens a little slower so I'm also in better control
The 4t is very easy to kick. It takes a long slow kick with not much force.
It gets better traction and seems able to regain traction easier if you do start to slip.
No mixing of oil or cleaning of oily exhausts.
It is hard to explain but it is more fun to ride, like a Reflex. Maybe it is the quiet smooth power.
That strong power on the initial blip tends to push the front end when doing full lock turns. To compensate, I changed my style to hold throttle steady and just use clutch in those situations.
Full lock turns do seem a little harder. It could be a higher center of gravity due to the taller engine or maybe the geometry is a little different.
The clutch is probably a little less progressive.
It only has 5 gears so feels like it is missing 6th. For trials it is fine but if you want to do high speed road it could be a limitation. The gears are nicely spaced, not like the old Shercos that seemed to be missing 4th gear.
Occasionally, after being dropped or stalled in some odd manner, it can take a number of kicks to get it going.
It has 3 oil filters. One is changed out and two are cleaned. It is actually quite easy and quick to do.
The carb is much more difficult to get out. Instead of a 5 or 10 minute jet change, it is probably more like a 45 minute or hour change....still not horrible.
Valve adjustments are a lot of work. You come very close to pulling the engine to get it to rotate down and get access. The recommended interval is 60 hours so it does not have to be done often.