The 002R has Focusrite Platinum range pre-amps, whereas the ProjectMix has the same budget pre-amps found in the M-Audio Octane. I'm also pretty sure that the Command 8 has Penny & Giles motorised faders, so you're more likely to have them last for years without any fuss. I've heard the ProjectMix' faders are noisey, and don't glide as smoothly as you would expect. Also, the ProjectMix' inputs can only be loaded with -10dBV signals, whereas the 002R will accept both -10dBV and +4dBu signals.
I would personally go for the Digi 002R with the Command 8. But, it's up to you. If you can justify the price difference, then definitely go for it. If you'd prefer the 002R and the control surface in one unit, then look at the 002 console.
Try out both set-ups. It really is personal preference.