What you use depends on what you are cleaning up.
Acid, such as vinegar, will help remove scale (calcium coming out of solution and depositing on surfaces, usually due to high ph) and disinfect to a degree.
But if your issue is an oily buildup at the waterline, acid will make things worse. TSP (trisodium phosphate) would be a better option for that, but I'd drain it first and clean it out before refilling as you probably don't want that in your water. But then, it's in many breakfast cereals, so who knows? I'm no chemist, like
@JoyfulNoise .
For general cleaning, if you have no specific issue, I recommend a no-scratch scrubby and a liberal application of elbow grease. Maybe a scrub brush or toothbrush for those hard to reach spots. Clean behind pillows, around jets, and the inside of the cover with a chlorine solution about 30ppm if mold is an issue.
@Ahhsomeguy has some products out that I would, and often do, recommend. Spa purge is a must, and he has a new product out that looks promising, though I have not had the chance to try it out myself yet.
Bottom line, if you are cleaning because it's a good habit, then it likely doesn't much matter what you use. If you are having an issue, then there is likely another problem that needs to be addressed that is causing it, and we would need details about your specific issue.