Are you using an in line filter or using unfiltered tap water into the steamer?
Some do not work so well with high TDS water and make wetter steam over time, less fluence.
Know the differences in actual component quality, not just if the steam generator has them.
Some have a higher gauge steel and hold up better with higher heat and constant usage.
Know the most common things that can go wrong if you use a steamer not built for your usage.
Most problems happen when people overuse a steam generator that is not made for continuous use.
Know how good a company is with servicing your steam generator.
Some of the best models have crappy service and vice versa.
Know the repair costs.
Some generators break down sooner but are cheaper to fix than the expensive ones.
Know the type of steam dispersion of the generator.
Some have high output but low fluence, and vice versa. Some have harder to breathe steam.
Know the energy consumption of a 20 minute session.
Some generators are not green and use more electricity than others for the same output.
Know if the temperature control of the room is controllable.
Most complaints happen when the steam goes from hot to allowing all the steam to escape before steaming up again.
I know the answers to almost any question about any type of steam question, steam generator, or steam room application. Make contact if you have a question that needs answering.