I think the better names would have been Barts pro = HD6830 and Barts XT = HD6850. A cut down Cayman could take the HD6870 name.
Personally, with so few changes to the 3d core, these actually look more like Evergreen family members to me, so HD5840 and HD5860. Especially since at least Cayman from the NI family apparently has way more changes there, so based on the 3d core alone Barts does not warrant a HD6xxx designation. I understand though the products aren't sold on internal architecture details.
I think some people will be disappointed with overclocking results (personally I'm not never expected anything better - this is still the same arch with the same clock design targets). Especially the HD6870 is a complete no-go for overclocking - results I've seen vary from 20-50Mhz on the core to 0Mhz to not much more for the memory. Naturally the HD6850 fares better though I guess this also largely depends on voltage (the reference card seems to have lower voltage than some retail cards which seem to use same voltage as HD6870).
Some people will also be disappointed about the lack of DP. Looks to me like it would be about time to support that on more cards.
Also, I think power management is a bit of a let down. Not to say it's bad (after all idle power still seems to be a tiny bit better than HD58xx) but it could be better. The cards still don't undervolt the memory at idle (which is a likely reason GTX460 is competitive in idle power draw). Plus, the cards actually took a step back from HD58xx with blu-ray playback - no longer underclocking the memory for some reason. Moreover, still using 1.6V instead of 1.5V for the memory, so power consumption could actually be better. Though I wonder if that overvolt is actually necessary due to the reduced frequency design of the MC to achieve stability (which really seems to have no headroom at all). Maybe that's also the reason even the HD6850 is using memory chips rated for 1.25Ghz rather than 1Ghz (another reason would be that they cost the same...).
In any case the HD6850 looks like a winner to me. Faster, cheaper, much less power consumption than the anemic HD5830 - this is the card with best performance/price and performance/power ratios. Nvidia might be willing to compete with that with the GTX460 1GB (which really is a more natural competitor than the GTX 460 768MB) but no way they are going to achieve performance/power ratio of the HD6850.
The HD6870 isn't bad but it's not much of an improvement over HD5850, at least not if you're willing to overclock (in which case the HD5850 will easily beat any HD6870). Plus the performance difference to HD6850 doesn't really justify the price difference.
