I’ve played around with a few of the alt firmwares to see if there’s anything I would use more often than the original granular/sampler mode but find myself coming back to that one because of how much fun I have with it. It’s the first module I got because of what it was designed to do (the utility of using other firmwares was a plus)
That being said, I’m curious what you all are using Nebulae for and/or if there’s an alt firmware that has become the main use?
The granular looper is a solid instrument, and really makes Nebulae the awesome module that it is. But, I love running the One Shot alternate instrument from time to time! Pairing it with a gate sequencer like Pulsar is a ton of fun, plus when you use the Blend knob to switch between 2 banks of samples, you can get some big sounds depending on the samples you are using.
Here is a quick patch example I threw together this morning. Pulsar in Euclidean mode is the main sequencer driving One Shot, with dual Nano Rands adding some modulation and resets to Pulsar and Nebulae. I have a Data Bender in there for some extra glitch sauce 
Alavon and Mars Affects of course 
I am working on an ‘enhanced’ one-shot (CV-ing the sample selection and/or volume), but I have trouble with the lag between CV values and triggers.