Debbie, whirlpool and jacuzzi are one and the same names for whirlpool baths. Jacuzzi just happens to be one of the first companies (from calif I think) to make them and it is just a jazzy name generically applied to whirlpools just like a spa. There are many good companies that make whirlpools/jacuzzis/spas. You are evidently looking for a replacement to a standard size tub. I call them whirlpool baths and some hip-hop teens from places like the left coast use the jazzy name. Guess I'm not a real jazzy guy.
Main thing is to physically get into each tub before buying to see if it fits your back both sitting up and laying down(some will poke you in the back). Same for your significant other. I wouldn't do without foot jets and read up on foot reflexology if you don't know about it. Look at the bottom of the overflow plate as that will be the water level unless you flip it over. Look to see if your knees will be sticking out of the water which they probably will. You want a deep a tub as possible at least 21" or more. Back jets are real nice. Make sure the side jets are located properly. Sometimes the middle jet of 3 jets per side will spray right into your hip hurting your hip. You also want an acrylic enamel finish. A 5 footer will leave your knees above water but if you are short, your feet may not reach the end and leave you feeling like you might slide in and drown. Also those real wide ones just kind of leave you swimming around.
Remember, try before you buy. I once made a home cheapo get a fork lift and take the display down from the top shelf so I could try it. Took over an hour and a request to the manager but it was worth it.