I don't know about this show in particular, but my experience with Doki is that they're typically prone to over smoothing, denoising/degraining (loses most of the fine details), and then over sharpening (introduces halos/ringing). So they've garnered a pretty bad reputation when it comes to their ability to do quality encodes. However Koten_Gars encodes are typically just done through Handbrake with pgs subtitles. So it really just comes down to user preference in the end whether you prefer fansubs or official subs, ass or pgs, filtering or unfiltered. A lot of people forget Doki exist though because they don't utilize Nyaa and so you've gotta check their blog or their own tracker that very few people utilize outside of Doki.

I experienced occasional very short instances of artifacts in three of the episodes and one very short instance of banding. Barely noticeable. Negligible, but present.