For no liquid cooling, I think that the phantom is great especially if you like the way it looks.
At $200 cheaper, I would definitely go for the phantom, and put some more fans in it. What features are there in the 800D that you like?
Reviews of the cases:http://www.guru3d.com/article/corsair-obsidian-800d-review-test/1http://www.guru3d.com/article/nzxt-phantom-review/
If you want, NZXT has a matching 1000w PSU. The corsair HX1000 is always a good PSU, and right now there is a good deal at newegg on the Antec TPQ-1000.