Yeah, it was originally developed by Nothing Real and then bought by Apple, so it doesn' t have an Apple-style interface to it. It could be compared to After Effects, but like I said, Shake is optimized to be pushing around absolutely gigantic (pixel-wise) feature film images. The main difference in the interface between the two is that After Effects and most other packages, like Final Cut, are timeline-based. Shake is node-based, so you' re building scripts visually by connecting the outputs and inputs of nodes, and each node has its own timeline within. So for example, you could have your source images and connect their output to an opacity node, and within the opacity node you would open up its timeline and set keyframes to fade it in or out. It' s just a bit of a conceptual difference in the interface, but I think the scripting structure of Shake is one aspect which gives it greater capabilities than other compositing software.

At this point I believe Shake has been discontinued and is going to be replaced by something currently called Phenomenon.

Digital intermediates for real movies are usually within the 2K realm (2,000 pixels horizontally, barely more than 1080p HDTV). That' s not too big, though back in the day when Shake was developed it sure was. Films that care about image quality have their digital intermediates scanned in at 4k resolution. I wish that were standard. Most DLP projectors at movie theaters are only 2K these days, though... so film still wins if the movie was scanned at 4k or didn' t have a digital intermediate.

If you see it while the film is new film wins, but its quality gets pretty bad after a while.

Only if you have a crappy projection booth staff who don' t know their heads from their ass (which is likely the case at most theaters). The longest film I' ve personally played is My Big Fat Greek Wedding which had 5 shows a day every day for well over 6 months straight. The film left without a single scratch, speck of dirt, missing frames, etc. If you run a professional booth, you get professional results... but most theaters these days have either the assistant managers running the show or some hastily trained concession stand monkey.