Temperature and humidity are the biggest problems I've tended to come across with shipping containers used for storage and workshops in the UK. I'm guessing your climate is not too dissimilar, though the Gulf Stream over here probably knocks off the worst of the peaks and troughs.
They obviously get very hot when it's hot and sunny and cold when it's cold, so are not ideal for actually working in. Lining them helps a lot though.
Running a good dehumidifier seems to eliminate pretty much all the condensation issues for much less power than heating them instead. We've used refrigerant dehumidifiers for years, but dessicant dehumidifiers look like they'd do a better job, especially in the cooler months.
If you use a space heater (gas or oil, no flue), condensation will be an issue. We've tended to find short periods of space heating with constant dehumidification are OK, but YMMV.
Room can be pretty tight with only the 8' width, but otherwise they are the cheapest way I know to get a secure dry building fast, assuming you can get one where you need to put it.