Sure, but it's just a brief initial impressions, as usually I need much more time for sound review.
In short — they are totally different
In long — iBasso is more neutral, less colored, more detailed, faster with dryer lows and more treble. Generally, this is technical, resolving representation. Sound stage of DX200 for me is really wide, but not too deep, so for some recordings it seems "flat", but on good recordings it's not that flat, but I'd like it to be deeper though. But staging is really subjective thing, so YMMV.
Fiio is a bit darkened, bass is a bit slower, mids sounds more "lively" to me (I think it's due AKs DACs) highs are softer and less present. So, X5-3 gives more soften representation.
For sure DX200 is better in terms of "technicality", but it costs 2+ times more, so it's pretty obvious. It's rival will be Fiio X7-2