Hmm, after finally getting to read the review once the dust has been settled here are my thoughts.
The GTX470 is 5~15% faster overall than HD5850. Sometimes it catches up to the HD5870, but most of the time its in between the two. On the other hand the GTX480 is 5~15% faster overall than HD5870. There are situations where these cards are 20~40% faster, whether or not its because of the game engine/cheat/etc remains to be seen. However the most eye catching was the minimum frame rates. Of all the reviews Ive come across, the performance difference is somewhat huge. I have several ideas of why this might be but the point is that Fermi based video cards will provide a "smoother" experience than the AMD counterparts. Some people have said its because of the lack of VRAM, but even at lower res they are beaten by a fair amount.
Performance is definitely lackluster for a 6 month delayed part, but give it time and driver maturity (seeing as it is a new architecture) I think we will truly see what video cards on Fermi is capable of. I can see how it resembles the R520/R600. The former was only 5% faster but soon stretched its legs as drivers matured to widen that gap (and even more so as games started to take advantage of S.M 3 and other complex effects). Both of these had power related problems, but were eventually fixed and were led to its derivatives that were quite impressive.
Which leads me to the other performance aspect of Fermi. Things like tessellation performance is impressive but how useful this is in the real world remains to be seen. If you are interested in compute side of things, then this is one of the shining points of Fermi. The benchmark numbers speak for itself. If AMD had a head start with process technology, tessellation and DX11 what not, nVIDIA has a massive head start on the GPGPU/compute side of things. No one knows how much openCL will take off (or in matter of fact GPGPU in general) but this gap could widen. If AMD does indeed take this path too, then their advantages when it comes to transistors/die size etc are diminished because of the added functionality/logic.
Power doesn't look too good for Fermi. However idle power consumption isnt too bad as i thought it would be. Its around 10~15W higher to Cypress based video cards. The GTX470 here doesn't look too bad in this compartment. It has a very minor advantage in idle power consumption and just a little higher at load compared to a GTX285. The performance between the two is quite big so its not a bad upgrade. Sound isnt a issue here seeing as its on par with the GTX275 (lower than GTX285/HD4890) unless your more sensitive to noise. If furmark stresses this card up to 93C, I doubt any games would ever make this card reach that level of temperature. This applies to every other card (much like how AMD cards failed on furmark but were fine in real world situations) Im not sure why people are bitching about getting better PSUs, when most of us have ~600W PSU with very high efficiency levels.
But the real problem here is the GTX480. Idle power figures are ok, but the load figures are up the roof. Imagine if a similarly clocked full fledged Fermi must've been like. Noise figures look worse as well, but I doubt this card can topple even the FX5800 ultra because it had a much whiney tone to its noise characteristics. Imagine running a 40mm fan at an insanely high rpm. However what AT have showed is the worst case scenario (aka furmark). So real world figures would be lower for all cards in that list.
All in all, I think the card to consider getting is the GTX470 if people are looking to upgrade from last gen cards now. The HD5850 on one hand is more power efficent, cheaper and less noisey but the GTX470 is better in both minimum fps and overall performance (With a similar power/noise characteristic of a GTX285/275). The latter handles DX11 effects like tessellation better, much stronger compute performance and has PhysX if that is of any interest. Im betting more performance from future drivers to come. 10~30% could be possible as they can now shift the focus to optimizing the performance rather than focusing on stability/compatibility.
GTX480 on the other hand doesn't seem to cut it. Its power characteristics are horrendous, and performance is lacking in comparison. However, if one was able to watercool these in an SLi configuration I would do it. Power isnt an issue, and noise wouldn't be an issue. Quite a dream setup for a selected few seeing as it destroys everything.