Yes, they are similar in size and weight to the old PST LP 120 and Faber LP 120.
The Faber 149 is 8" in diameter, 29.5" long, weighs 47 lbs and is +2.35 lbs bouyant when empty.
The PST 149 is 8" in diameter, 29.4" long, weighs 47.5 lbs and is -1.7 lbs bouyant when empty.
The PST LP 120 is 8" in diameter, 29.4" long, weighs 51.3 lbs and is -1.7 lbs bouyant empty.
The Faber LP 120 is 8" in diameter, 29.0" long, weighs 45 lbs and is neutral when empty.
One thing to consider is that the PST tank is most likely not going to be available anytime soon until they get their production and distribution mess straightened out. The Faber 149 is available but at +2.35 lbs bouyant when empty will require 4 lbs of weight per tank to get you back to where you would be with most 3442 psi 100's 120's or 130's. So if you are properly weighted with your configuration with 100's 120' or 130's, you need to add on 4 more pounds of lead per tank which effectively makes the total weight per tank 51.5 lbs - right in the LP 120 ballpark. So they are no worse than LP 120's, but they are a lot heavier than the 3442 psi 120-130 cu ft altrnatives.
There are lots of option in the 120 cu ft range and the 3442 psi tanks in that range are in general either 8-9 lbs lighter or 4 " shorter and may be a better choice trim wise for an under 6 ft diver. 3442 psi 130's tend to run about 4 to 5 lbs lighter and 2 to 3 inches shorter than the 149's.
If you absolutely need the gas, the 149 is an option, but if you don't need the gas for most of your dives, I'd go with a lighter and shorter 3442 psi 100's, 120's or 130's. When comparing 3442 psi 120's with Faber 149's and the added lead needed for the same bouyancy with empty tanks, a pair of Faber 149's would be about 26 lbs heavier at about 83 lbs versus 109 lbs with bands and manifold.