I was in the same boat where I was using a power meter (Favero Assioma) when I upgraded from a wheel-on smart trainer to the KICKR Core almost 2 years ago. I can’t say the difference was necessarily night & day like many who’ve gone direct drive, but the ride feel is definitely different and gradient changes are a little smoother. I don’t think I settled by not getting the flagship KICKR for a few reasons:
1 - the included 11-speed cassette would have done me no good, since the bike I keep on the trainer is a 10-speed
2 - even on my best day I’ll never see 1800 watts let alone 2200 watts the flagship KICKR has as max resistance
3 - I use a power meter as my power source anyway so I just needed something to replicate the gradient changes for realism
Even though I’ve never used the Core as my power source on Zwift, I’m confident it would work well if I had to based on the reviews. Honestly, I got the Core because I was curious about all the hype about direct drive trainers.
Don’t get me wrong, it’s nice and you can spend as much as you want on a high-end setup to enhance your experience, but at the end of the day you still gotta put the work in whether your trainer cost $200 or $1200. That’s what I remind my friends who are getting into cycling and indoor training as we head into winter here in NY USA.