I prefer VirtuaLight.
Reasons: Excellent raytracer. Superior antialiasing possibilities, all the way up to level 10 super-adaptive. It also has undersampling which is great when you want a really quick testrender. The shaderlanguage is incredibly flexible, still fairly easy to use. It features advanced shader options such as chromatic dispersion and absorption. Subsurface scattering is coming too, though it’s not available just yet. It’s got a very good Monte-Carlo irradiance algorithm, useful for both indoor radiosity style pics as well as outdoor skylight/sunlight renders. On top of this you get photonmapping, reflective and refractive caustics and participating media such as Rayleigh (molecular level) and Mie (fog, mist, really small water droplets in the atmosphere) and two other models (isotropic and henyey-greenstein with variable excentricity). You get arealights with neat soft shadows, blackhole lights, and all other standard kind of lightsources.
On top of this it evolves rather fast. Stephane Marty, the author of VL, keeps churning out updates on a fairly regular basis, though it’s slowed down a bit lately.
The downside is that with all options switched on, you can easily get scenes that takes days to render. But then again, you don’t have to use all features all the time.
Umm… I’ve got more to say, but this’ll suffice for now.
EDIT: U asked about DOF too. VL supports that as well, of course. And a couple of different cam lens models to choose from too.