I only had my cab 3720 for a few weeks but do drive large ag tractors with cabs. No doubt about it, cabs are nice to work in. Mowed 6 hours with it yesterday. The upside strongly out weighs the downside.
UPSIDE: Can work comfortably in almost any weather. Much quieter. No dust, bugs, exhaust fumes etc. Cabs have rear view mirrors for road travel. Can easily listen to radio. Can't hear my wife yelling at me.
DOWNSIDE: Overall more difficult to get on and off seat. Sometimes so quite can't tell if having problems with tractor or implement. (ie scalping ground with mower, tractor lugging too much, something broke on implement or tractor, implement hit something), Difficult to get someone's attention - can't yell through glass (considering getting a horn). Perception that uneven ground seems rougher than open station (I believe this is due to cab movement on rough ground give sense of greater motion). On relatively cool days still need to use A/C because of greenhouse effect of so much glass. Can't see rear wheels because of tractor fender/cab (sometimes difficult to tell if wheels spinning or not).
Improvements I would like to see:
-be able to get off/on either side of cab. However this is the case for most cab tractors. Some ag tractors can get off/on both sides.
-quarter rear windows that open like Kubota has. Our ag tractors have these and on cooler days, you can open windows to get cross ventilation. Dont get good air flow with only rear window open.
-option for more tint to glass
-reversal of placement of 3 pt lift control and 3rd/rear hydraulic control. 3 pt used much more than hydraulic.
-no visual method to determine if in A,B or C range or control lever. Kind of have to use sense of feel and general position of lever. Electronic indicator on dash?