I wouldn't use so dramatic a term for it but, for some people, yes. The BFL product is most advantageous for those with high electricity costs and/or logistical issues with GPU mining side-effects. After all, any efficient GPU has 2x the hashrate/$ ratio as the BFL (5970: $300@800Mhash. BFL: $600@800Mhash. Replace '5970' with 5870, or 5850 or 5830, and the same ratio applies).

You can find used/refurb 5830's for $75 now and they will get ~275Mhash; that's almost a 3x better Mhash/$ ratio than BFL. Yes, I realize that over the longer term (the exact length of that term will be different for everyone) the lower electricity costs of the FPGA will overtake the initial cost savings of the GPU ... but I'm putting that aside for now.

In my case my GPUs run in my home; I've reached the point where I cannot add any more mining capacity without compromising comfort (heat, noise). These BFL boxes will (a) let me add a bit more capacity; and/or (b) replace some GPU capacity with FPGA.

If I had the option of running my GPU rigs outside my living spaces, I'd pick up more cheap GPUs, not BFL Singles, simply because of (a) the lower up-front capital outlay for GPUs; (b) the expected higher resale value of GPUs; (c) the better warranty of GPUs; and (d) my low electrical rate.

Everyone should run their own 'cost/benefit' analysis before deciding what is best for them. I'm sure the BFL boxes will be popular with many people, but they won't be for everyone. Once I see they are shipping and have read some positive reviews, I will buy up one or two myself just to see how well they would work for me.

YMMV.