Here in Vancouver I have worked with "Relax - A - Mist", "Mr. Steam" , "ThermaSol" and "Roma" steamer units. Of the four I like how quite and fast the "ThermaSol" unit is the most. I would say the "Relax - A - Mist" is the cheapest unit of the lot but does offer up a goos steam shower experience. The ThermaSol warranty and self cleaning features outstanding.
There are very little codes in regards to Steam Showers so when your planning your project understand that these units can most times just be dropped next to the steamer and hooked up. I would advise you to follow the commercial guidelines and opt for extra safety and piece of mind. Consider placement and service of the unit in your bathrooms lay out.
Come back and let us know what you decided and why..