Got rescheduled on a Thai Air flight after my EVA flight was cancelled because of a strike. I usually travel premium economy so this comparison isn't really fare but does reflect my experience.
I found the seats a nightmare. Uncomfortable and not enough leg room. Would hate a night flight. Food was just ok but not as good or as varied as I'm used to. Too many children (no offence intended) - kicking back of seat, running in aisles, crying, etc. Large selection of films but quality not great. Cabin crew did a good job.
Overall this confirmed to me that paying extra for premium economy seats is worth it for me. It's a shame Thai Air don't have this category. I would consider them but as it is I'll go back to EVA.