Unfortunately, Avalon chips are so inefficient, that the delay means negative ROI by the time you get your boards built and mining. Even if Yufi decided to refund everyone and give you the chips for free!
The recent difficulty jump has made any ASIC over 3watts per GH/s not viable unless you get dirt cheap electricity. Which means ASICminer, Avalon, BFL are now all pretty worthless, and orders should be cancelled until a more efficient chip is available. The only savior would be if we see a massive rise in BTC/USD price which, to my surprise, has not moved to reflect the change in difficulty. I expected BTC/USD to be back around $200 now, with miners refusing to sell new coins for any less.
The inability for ASICs to cover electricity costs is a serious issue. Look out ASICminer shareholders!
Here is a mining ROI calculator with presets for most popular miners
http://mining.thegenesisblock.com don't forget to set your local electricity price correctly first. The default is 15cents/kWh mine is 24cents!