I have rented from both Special Needs at Sea and ScootAround and always check pricing on both. For my upcoming 14 day TA from Rome to Miami, Special Needs quoted me $642 and ScootAround was $395. Pretty obvious which one I chose. BTW, I own a Tzora but it is too heavy for me to take apart and travel with by myself.
For long (14 day or longer) cruises, I pack my at-home concentrator by INOGEN (weighs about 20 lbs) along with all of my batteries and plugs, etc. It is free to check and that way I don’t have to use my POC at night.