When you read about someone else being overwhelmed or underwhelmed with certain IEMs, in many cases people are talking about their sound preference relative to other iems they are used to. Just from my personal experience, I had a chance to test/review a lot of flagship iems, and I honestly never came across one that was bad. When it comes to flagships, every manufacturer brings out their a-game. But not every a-game is everyone's cup of tea. We all have different sound preference, listen to different music genres, pair up with different sources, have different hearing sensitivity etc.
I'm looking at your sig and see K3003i and FX750. Is one better or worse than the other? How about EL8C vs P7? All different sig, each one good at their game with different sources, different music genres, and even different cables that can give you a subtle fine-tuning. I never heard IE800, but many refer to this ultra-wide bandwidth DD as having a very obvious v-shaped signature with a lifted bass and more energy in upper mids/lower treble. If you are used to that sound, switching to W80 will give you an ear shock due to a warmer, smoother, more laidback and less revealing signature relative to IE800, while some other people going from W80 sound will find IE800 bass having too much impact and treble being too shrill and crisp (I looked up IE800 FR curve). Is either of them good or bad? Not really, just a different signature and a different tuning targeted at different people.
@MacedonianHero gave
@hstubc a good advice, give it some time for your brain to adjust to a new sound, especially without constantly going back'n'forth between two pairs of IEMs with a different sound sig. I don't have UERM, only UERR, and it's in a different ballpark, a different signature.
It's up to you if you want to cancel the order, but only your ears, not someone else's, will tell you if you will like it or not. Reviews and impressions give you some guidance of what to expect, but you will be the final judge. That's why those who are in doubt, for example, can attend CanJam London where Westone will be showcasing all their iems, so you can take a listen. If you don't have access to these audio shows, as long as you can buy and return it back (if you don't like it), that's the only true way to find out if they are good for you