I own two aerotanks. The original and a v2. The differences between the two are very small. I really like the new airflow control base on the v2, so I purchased one for the original aerotank. With the new base it's almost indistinguishable from the v2. So take away is that the base makes all the difference. If you're looking at an aerotank just for the airflow control and you like your protank, then buying just the base might be a good bet. If you want a second
tank either way then the aerotank is a good bet.
One important note to be aware of...
When I bought the v2 it came with a different base than I'm using now. It seems there was a first run of aerotank v2's that used a different base than they are now using. I bought my aerotank v2 from MVS, and they sent me a replacement airflow control with the new style.
New style looks like this:
MVS is selling the new base
here. The pictures are not updated yet, but I can confirm they are shipping the new one.
EDIT: Looks like they are sold out. Bummer.