Depends on the type of diving, configuration (singles or doubles, wet or dry) and availability of fills at high pressure. IMHO for singles diving there is no better tank than PS HP-120s as long as you can get them filled in where you intend to go diving. I am looking forward to the new super duper Pressed Steel tank but have yet to see one. The local LDS here where I get Nitrox as well as the dive operators Ive dived with in North Carolina all bank Nitrox at higher pressure so Ive had no problem.
I am only doing no decompression, no overhead diving. With a HP120, even though Im somewhat of an air hog, typical SAC 0.7 cfm, I reach the NDL or just get board before I have to surface based on air supply. The HP120 allowed me to drop 6 pounds of lead compared to an AL-80 and weighs about 14 pounds less than the comparable LP tank.
One drawback I've seen is that because of the shape of the tank it tends to make you a bit head heavy.