I like these impressions. This definitely fits in with the traditional sound signature of the IE8x line. The IE8 still has the most expansive soundstage I've ever heard from a IEM in its price range. And yes, "fun" and "not neutral" is much better to me than the sterile, unengaging neutrality the IEM market seems to be desperately striving for in recent times. Not every earphone needs to be a monitor, and fun can be achieved without bloated, muddy, exaggerated bass as I've found for example in V-Modas. The bass in the IE8 and IE80 is prominent, but not booming, very fun and precise.
I also find the "Sennheiser veil" to be much more of an issue in full-size earphones. The Momentum and the HD-5xx series definitely sound a bit off. The IE8 and IE80 instead, I've always found lush, full, engaging, fun.
I'll have to give the IE80S a try, even if I'm afraid that it may just be a more expensive, slightly refined IE8.
Did you have any trouble with the fit? Can you make a comparison in ergonomics with the IE8 or IE80?