Actually it's the Miller 180, the 175 was discontinued last year. I wanted a 220 and this seem the best bang for the buck. Kinda wish I'd gotten two small tanks instead of the midsize one.
With two you don't have to return a nearly empty bottle to make sure you have enough for the next project. You can completely empty one bottle and have the next in reserve and keep rotating.
I was going to trade in my 80 for the next size up, but I think it will be easier to have 2 80's. They're also easier to transport.