At the current price, not at all. Unfortunately the frenzy for the Eruptors has caused their price to be ridiculous. So the return just isn't there. On the other hand, if you can get your hands on one of Avalon's units or a fabled BFL unit the return is there. The Eruptors really only make sense if you are buying in large quantity. If it costs you more than $250 each there's no way you'll ever get the money back unless BTC makes a huge jump in the currency market. They really looked like they were going to become the mining unit of those without the funds for larger rigs, but so far the prices are too high to make it happen.
So it looks like the Avalon units are around $300 for 4.5 gh/s of hash power. Is this something that you think is feasible in terms of money and hash power?
ASICS will be giant useless paperweights if Bitcoin ever crashes. I would never wager so much money on something so volatile honestly. I am talking about the more expensive ones though, at $300 its worth a shot at first but eventually even that will not be enough to make much.