Way back when I got my first bottle, I looked at renting vs. buying the bottle. Renting made sense if you used it a lot. If you had it filled up every so often (I forget how often) there wasn't a charge for the bottle. However, I knew mine would sit for months between uses so I bought the bottle. Actually "bought" the bottle as it is really something like a 99 year lease due to some sort of legal issues with bottles, pressure testing, and such. They still swap bottles when I take mine in for a refill -- I don't get the same one back.

I was checking that DVI model out as well. One nice thing would be the option of 110 or 220. I have 220 in the shop, but it would be nice that I could take it over to a buddy's shop and weld for him even if he did not have 220. Sort of pricey, though. Been looking at plasma cutters as well and don't think I could swing a new MIG and a plasma...