I don't have a curtis cab on my M59, mine is the Laurin. For me the BH goes on and off easy I only have to remember to unhook two latches securing the top of the BH cab extension.
The hardest part is installing the cab filler plate when the BH is taken off which only requires me to remove and re-install four M8 socket head cap screws using a long M6 hex driver with a ball end on my screw gun. Three of the screws are easy, the fourth is down low behind my remotes and a PITA to get threaded back on. I have to remove and re-install the back window using two large pins up top. I need a ladder for this part. Overall it takes me 30-45 minutes to swap, usually faster going to the BH.
My cab is quieter than open station but I still need hearing protection. In winter I can clear snow wearing nothing but shorts at -30oC. In summer I roast for about two months and inside the cab it gets to 40+oC with the windows open. Save yourself some sweats and install a separate ball valve to stop flow at your engine compartment to your heater core in summer.
If you are installing the cab make sure to buy some foil backed sound deadener and insulate your cab floor from underneath before install. I'd also install it under the inside ceiling panel and under the engine bonnet.
If you are in a hot climate you will definitely want/need the A/C option $$$$.
If you are spending the money cry once and buy an air ride seat option at the same time. Look up my other posts for pics on my seat upgrade.
Once of these days I will take the roof off and install a 12" wide exhaust fan to help summer air flow.
