"Big Sur" is still being edited and it was made without a distributor in place, so I can't say when you'll start seeing any clips. I'm hoping that it will play at some film festivals next year, like at Sundance, but we'll see.
I'm hesitant to make a final judgement on any camera or film stock without having done the final color-correction and seen it projected. So far, I've only seen some shots in a D.I. theater and played around with them. What I've mainly noticed right off the bat is how clean the Epic image is even at high ratings like 2000 ASA. The lower compression rate and wider dynamic range also play into giving the image a lovely, smooth, clean look that is not plasticy or electronic in texture. Can't say too much about color since the whole look of "Big Sur" is desaturated, but when I've seen of my shots pre-desaturation, the colors look very natural.
It's not far off from the Alexa look, which is a bit softer as you'd expect. The sensor or low-pass filter inside the Alexa also seems to cause a mild glow around light sources in dark scenes. Alexa is the king so far in overexposure latitude though Epic is not far behind.
There's no right or wrong approach here but the Epic being a small box has certain advantages and disadvantages over the rectangular shape of the Alexa. The advantage is obviously that the camera can be stripped down into a small box with all of its processing and RAW recording capability still intact. Anything small & lightweight will be an advantage for certain types of shots. The disadvantage to the modular approach is that the camera can become a mess of accessories, arms, plates, etc. needed to attach stuff.
The Alexa, on the other hand, being close to the classic camcorder design (which should get more praise than it has) quickly goes from handheld to studio to Steadicam mode with hardly any accessories needed. The menu system is also very well designed. I didn't get to use the Redmote that comes with the Epic so I can't say how it compares in terms of ease.
ARRI realizes the advantages to a smaller profile camera hence the new Alexa-M ("M" for modular") announced at NAB, which basically splits the camera in half so you have the sensor & lens in a small unit. Great for 3D rigs. But it's not self-contained like the Epic, you still need to be cabled to the other half of the camera plus a data recorder of some kind as well if you want to record RAW instead of ProRes.
I like both cameras, Epic and Alexa, and which I'd choose would depend on a number of factors, from how much resolution I wanted to have available to me in post, to how quickly I felt I could work with either cameras in a run & gun shooting situation. But considering that "Big Sur" was shot in 21 days, clearly I was able to work pretty quickly with the Epic on a set with minimal crew members.
Obviously Roger will have his own opinion about this, but if he were going to do some sort of landscape movie with a lot of big vistas, I think he should seriously look into the Epic, check it out. On the other hand, once Alexa comes out with an optical viewfinder, I think Roger is going to be so happy that it will be hard to get him to consider something without one...