Most users on here choose a heater based on their own personal application. They pretty much all do well. As an example : some heaters go under the seat, this is where some users like to add a full size second battery. You cannot have the battery and heater box under the seat. Some people like to use the dash mounted system. I have heard this is very tight and can be slightly more difficult to install.
None of the soft or hard doors from any brand fit perfectly. This is mainly due to the slop tolerance Honda uses during construction of the ROPS. To get any true seal will require additional modifications. Even then most users will state it is not 100% sealed. Pretty much all the name brand doors are decent. OEM, SuperATV, and Siezmik are typically the top three used on here.
I will recommend a name brand winch for best results. You want it to work when you need it. Do not use anything smaller than 4500. Synthetic rope is highly recommended. Viper, and SuperATV are probably the most used winch brands on here.