Sounds fabulous! Congratulations with a worthy addition to your collection!Need some time to listen more but some initial impressions:
Bass is leaner on the Sun Copper vs the Serratus but it is cleaner - not as much rumble as I'd like but it's very detailed. Serratus wins in sub-bass extension and rumble, Sun Copper wins in clarity. No other bud I have heard has sub-bass quite like the Serratus but they are very different - like comparing apples to oranges
Sun Copper mids are probably the cleanest I've heard in any transducer - it's making everything else I listen to sound fuzzy on A/B.
Treble is very airy and sparkly - very well-extended and very natural sounding. Similar to Serratus in this respect here - need more time to compare though.
I can already say Sun Copper's resolution is best in class from lows-to-highs (among the transducers I've owned or heard). I'm hearing details I've never heard before in songs I've heard a million times before regardless of transducer type.
Stage is very wide and deep with great separation and imaging. I think Sun Copper takes it by a hair here as it does have better separation and more precise imaging and positioning. The Serratus does sound a bit more like a 2.1 system though which is super nice.
One thing to note: Sun is a tricky fit - takes some playing around to get it seated right but it does stay firmly in place once!
How do you feel the Sun Copper compares to the Ripples?