Well, the material we're working on is currently confidential, so I cannot show it publicly unfortunately. But I'm curious to try out Natron because like previously explained it handles large EXR files much faster than Adobe After Effects. I did some reading and playback experiments with various single and multi-channel composites, and Natron outperforms After Effects by a long shot when doing the exact same thing.
But the other reason I'm interested in trying Natron is because it provides more technical tools similar to NUKE. I can explain more specifically what I'm talking about, it might sound like a minor thing, but it's actually quite crucial in this case.
The EXR files are actually baked textures from 3d software (in this case 3dsmax/Vray). To capture what is going on on the surface of the complex 3d mesh I'm using an duplicate version of it with each face offset along its normal. By capturing the reflection of this offset mesh I can capture what goes on on the surface, behind or in between the surface. I'm not restricted to produce effects entirely on a texture level.
The problem however is that the baked texture (the EXR files) cannot be rendered with edge padding (produce an extra margin beyond the UV border), a feature otherwise supported when baking texture to files. This is because rendering with padding will make the offset surface see details of surfaces it's not supposed to, and you get something that looks like artifacts along edges. It's not a bug, but a logical error I think.
I can however pad the texture in post, simply by layer a blurred version of the texture below the original, and then adjust the levels of the alpha channel, pushing the input white down to something near zero.
I can do this in After Effects, but Natron gives me a much better result, quicker.
Without edge padding you risk getting dark edges along UV borders once the texture is applied to a 3d mesh inside the projection software. It depends on how precise the filtering of the texture can be made, but often such projection software favour speed rather than quality, and that might lead to visible dark edges along UV borders.
And HAP is as you probably know popular for realtime streaming of large material, so add it to Natron and you'll have one happy user