I see those Naver translated web novels popping up all over the place lately, mostly on aggregator sites. Honestly, the quality feels all over the map.
Some of the translations I've tried read like they've been run through Google Translate twice, with character names changing halfway through a chapter and sentences that just don't track logically. You can tell nobody bothered to proofread.
But then, I stumbled across a translation of 'Omniscient Reader's Viewpoint' from a Naver source that was actually pretty smooth. The dialogue flowed, the jokes landed. It made me think the reliability isn't about Naver itself, but about which fan translator or group picked it up. The raw source might be solid, but the final product depends entirely on who's doing the work.
I usually check the comments on a site before diving in; if readers are complaining about the English, I just back out.