While there are at least 3 (maybe more) dive ops on Cozumel that offer Steel 120 tanks, they are not, I believe, all HIGH PRESSURE Steel tanks - rated for 3500 psi fills. Aldora's tanks are HP Steel tanks, which, because of their higher fill pressure, are more compact than the low pressure (really, mid pressure) steel tanks that are only rated for 3000 psi. The LP Steel tanks are both longer and a bit fatter than the HP Steel tanks, while the HP Steel tanks will be a bit heavier as a result of thicker cylinder walls. If you are a shorter person, say 5'8" or less, you might find both tanks too long, swinging down and hitting you in the ass while you are in the water, lifting your BC over your head when you are seated on the boat. If you are 6'4" or taller, the extra length of the LP Steel 120 probably won't bother you a bit. If you fall between these extremes, the more compact HP tanks might be more comfortable both on the boat and in the water than the larger LP Steel tanks. Also, the HP Steel tanks are more subject to "short fills" because of the higher temperatures generated when filling these tanks quickly; if these tanks are filled quickly to 3500 psi, they might only show 3200 psi or less when allowed to cool. This can be avoided by a slow fill of the tank while submerging it in cool water. So the method of filling these tanks can also make a difference in tank performance.