Not personally but I was in a small clipper <20' during the '09 Madison Intl rally. The owner installed on of the in a closet to effectively hide the unit. That trailer was as cold as a meat locker!
The local Fleet Farm gas and service store also used one of these. It seems to do an OK job with many people going in and out.
It still must have an exterior duct.
Personal opinion? I'd go for something more permanent that doesn't take up floor space or reduce headroom and something quieter than the typical RV furnace & overhead AC.
A split system might work until it gets too cold outside or its gets too humid inside the trailer. Check with the manufacturer.
I also have questions on long term durability of a split system if the unit is towed extensively. But others can chime in with their experience.
Plain old window A/C units have been used and are cost effective. They can be mounted so as not to be an ugly appendage.
Heat appliances will depend on your use and if it involves dust, fur or fumes expected inside.
Also, what power is available? How much floor traffic? Lighting that will supplement heat or make cooling more difficult.
I've seen diesel floor heaters adapted from a buss, electric floor mats, mini boiler systems with floor heat, Cat heaters, furnaces, solar with external heat collectors, etc.
Use, travel, power available will all direct you choices.