...meant to say "more snap and shallower depth of field..."
Correct. The standard focusing screens in all modern dSLRs are laser microetched to provide a brighter viewfinder for typical consumer lenses, the majority of which are f/3.5-5.6 or something similar. The consequence of that laser microetching is that lenses faster than f/2.8 (e.g. f/2 or f/1.4) show the depth of field of about f/2.5. With a fast lens, it's easy to confirm this, just hold down the DoF preview button as you stop down, and you won't see the viewfinder get any dimmer until you hit about f/2.5. The light is still getting in, it's just blocked by the focusing screen. Interestingly, you can directly see this on the 7D, because light 'washes out' an LCD display. So, with my 7D and 85mm f/1.2L II, stopping down from f/1.2 to f/2.5, the viewfinder gets no darker, but the transmissive LCD showing the AF points does get progressively less washed out (on a sunny day at f/1.2, it's actually a bit hard to see the AF points).
Screens like the Eg-S for the 5DII offer a brighter VF and show the true DoF for fast lenses. But the consequence is a dimmer VF with slower lenses, so it's hard to see to compose, let alone focus, with an f/5.6 lens in a dimly lit room.
