CAT will give you ROI more faster than every ASIC hardware out of there. I have done 0.25 in 2 days using 2.5/3 BTC.
I think CAT works very well but I think to talk about ROI is slightly misleading. Yes, gain is guaranteed but it is not Bitcoin gain guaranteed. You are guaranteed to gain in altcoin. I have been using CAT for a few weeks and definitely have more altcoins to show for it. But I don't have more Bitcoins to show for it. My available balance on Cryptsy has actually decreased because of Bitcoins increasing value/altcoins decreasing exchange value. So I have actually seen a loss in Bitcoin since buying CAT with Bitcoin, but I do have more alternate coins. If those altcoins ever increase in value, then maybe I'll have an ROI but if they never do, there's no ROI. That's why I think you to say that CAT will give you an ROI is a little misleading. If you don't think altcoins have value, then CAT is not really for you and then comparing CAT to an ASIC doesn't make sense either.
Actually, what would be a neat feature is that once you make a successful gain ping/pong, there would be an option in CAT to automatically withdraw that gain portion to an external wallet and then continue trading with the original value of BTC.