I've never been attracted to Neptune, but Goshiki on the other hand quickly grew on me. Perhaps it was partly because of Sunset Aquascaping? I waited for that Lucky Catch update and pretty much attacked the daily update thread to see what shiny new things we got for the month, and the Aquascaping's instantly appealed with the transparency poses and tail. Though now that the excitement over new items settled, I can see many more aspects about Goshiki that I prefer over Neptune.
I'm not fond of dressing my avatars in too strong colors, but it's fine for details, which is exactly how it's used in Goshiki. Neptune is an older scheme, so there's some variety between the items, but I definitely prefer when it's combined with brown/offblack over gold. The teal and gold together makes me think of colorful parrots. I don't mind seeing colors like that, but less interested in wearing it. Neptune teal with brown is however very much like other existing combinations, the gold makes it less forgettable as a scheme.
While Neptune can be a little tricky because the items have less consistency due to being older, Goshiki is the exact opposite. I had two Goshiki items to work with and neither has any proper male poses. With most color schemes, I wouldn't have been able to pull off an avatar, but Goshiki can essentially be made from Poppy and Neptune. It's brilliant, anyone can wear Goshiki with some creativity, without actually using Goshiki items. I hope gaia does this with more color schemes, it will really help with the lack of making items with actual pants in some color schemes. That is a growing concern for me, most new color schemes don't have any male items, besides maybe a hair item or two.
The downside with Goshiki is that it can be summed up in 'nautical + anime'. There's nothing stepping outside of these boundaries, even the latest Goshiki item in Narwheel follows that rule.
(It's this one in case OP wants to add it to the list -

)
Neptune is at least a color scheme with great item variation, making so many more themes available. Can be tricky to combine some of the items, but sometimes a solid theme beats perfect color coordination.
Adding my avatar in post in case I change it again. I decided to go for Goshiki, heavy on the poppy and white. As always, I need dragon recolors. I tried to work in a
Draconis Lucem, but alas, the yellow stood out too much. That dragon would be perfect in Goshiki though, makes my brain twitch in the direction of tie-dye tickets.