NZXT has pushed into the 200+ USD category with the Phantom 820 and has done so quite well, but is there room for such a case as the Phantom 630, or will it befuddle the end user's thoughts on which chassis to buy? Savings around 50 USD also means giving up the HUE controller, a more capable fan controller, and true hot-swap bays, and the Phantom 630 is still of a similar size, not providing the advantage of a more compact chassis.
In summary, the NZXT Phantom 630 is a very good chassis if you do not want the tricks and features of the 830, but require a case of similar size. It actually does improve on the ODD locking mechanisms found in its larger brother, but I find the fact that the hard-drive trays are still flimsy dissapointing. NZXT seems to have changed them ever so slightly, but they are still not up to snuff for a 200 USD chassis.
At the end of the day, the Phantom 630 is to the Phantom 820 what the Phantom 410 is to the original Phantom 3.0: a slightly smaller case with a similar look and approach. This is by no means a bad thing and the Phantom 630 is a great chassis, but the question of whether its well-endowed target audience will fork out an additional 50 USD for the Phantom 830 instead of buying the 820 remains to be seen. If you would rather spend the 50 USD on hardware instead of an 820, the Phantom 630 does come with the genes of the 820 and a few improvements, but without the extra "cherries on top".