An operator I know is remodeling his tunnel. He only has room to put one additional arch in his short tunnel. He is not sure if he wants to put in hot wax or one of those super sealants like RainX. I have a personal bias in favor of a super sealant because it affords more protection than hot wax but I know hot wax puts on a better show in the tunnel. If you had to choose which one would you pick?
IMHO, hot wax has the same longevity as the super sealants. I have used rain X as well as other super sealants and they do not last any longer than hot wax and shine. I should say hot wax lasts every bit as long as any of the other sealants and provides a better shine.
I put it on with k nozzles - no lava applicator for me, but the results of the product speak for themselves. Both types of products offer around 30 days of protection. By the time that time is up, most customers have returned for a wash. If not, then they are not too concerned about shine or protection!
Also, operators who offer both, always save the hot wax for the highest package. If customers are used to seeing the hot wax placement in the highest package at competing washes, they will want to see it in the top package at your friend's wash - even if he does not have a super sealer on the second package.
I would go with the hot wax.