Numerous benchmarks abound for this card.
Best deatures would have to be DX11 support.
Eyefinity multimonitor support
Cooler running and a bucketload faster than the 4000 series on the whole.
Downsides so far is the initial cost making it NOT so attractive to hose that already own good gear.
http://www.staticice.com.au/cgi-bin/search.cgi?q=hd+5870&spos=3
Australian sites ranging from a good $448 to $580 and very limited supply it would seem for the 5870
http://www.staticice.com.au/cgi-bin/search.cgi?q=hd+5850&spos=1
From $369 to $434 for the 5850 so a little better but still to high for most.
Also the beta release drivers are out from ATI and DO install on older 4000 series cards and add afew features as well as perform well (so far)
http://support.amd.com/us/kbarticles/Pages/ATIRadeonHD5800seriesrecommendedgraphicsdriver.aspx
Of course no support on windows xp yet but hey..move on 
Below Links were stolen for www.overclockers.com.au and digital monkey(he works to hard)
- ATI Radeon HD5870/HD5850 Review Listing:
General HD5870 Reviews:
- Guru3D: http://www.guru3d.com/article/radeon…0-review-test/
- Hardware Cancucks: http://www.hardwarecanucks.com/forum…r5-review.html
- Legit Reviews: http://legitreviews.com/article/1080/1/
- HardOCP: http://hardocp.com/article/2009/09/2…eo_card_review
- PC Perspective: http://www.pcper.com/article.php?aid=783
- Hexus.net #1: http://www.hexus.net/content/item.php?item=20289
- Hexus.net #2: http://www.hexus.net/content/item.php?item=20354
- Tom’s Hardware: http://www.tomshardware.com/reviews/…5870,2422.html
- AnandTech: http://anandtech.com/video/showdoc.aspx?i=3643
- Bit-tech: http://www.bit-tech.net/hardware/gra…0-1gb-review/1
- TweakTown: http://www.tweaktown.com/reviews/293…ard/index.html
- Legion Hardware: http://www.legionhardware.com/document.php?id=858
- PCGamesHardware: http://www.pcgameshardware.com/aid,6…-card/Reviews/
- Hot Hardware: http://hothardware.com/Articles/AMD-…ly-Number-One/
- InsideHardware: http://www.insidehw.com/Reviews/Grap…ce-GTX285.html
- FiringSquad: http://www.firingsquad.com/hardware/…mance_preview/
- TechReport: http://www.techreport.com/articles.x/17618
- Xbit Labs: http://www.xbitlabs.com/articles/vid…on-hd5870.html
- Driver Heaven: http://www.driverheaven.net/reviews.php?reviewid=842
- HardwareZone: http://www.hardwarezone.com/articles…?cid=3&id=3012
- OverclockersClub: http://www.overclockersclub.com/revi…pphire_hd5870/
- Overclock3D: http://www.overclock3d.net/reviews.p…ddr5_preview/1
- Bjorn3D: http://www.bjorn3d.com/read.php?cID=1682
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- Radeon HD5850 Inclusive Reviews:
- TechPowerUp!: http://www.techpowerup.com/reviews/ATI/Radeon_HD_5870/
- TechPowerUp! Xfire: http://www.techpowerup.com/reviews/A…870_CrossFire/
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