"I finished this and didn't hate it" sounds a little... damning with faint praise... but yeah, sometimes "kudos" is a way of saying "You managed to get me to read this all the way through and it was OK", which may be lower on my scale than "Good job/I liked this", but is at least higher than things I click away from.

If I get to "I ADORED this", then I'm in leaving-an-actual-comment territory, even if it's just to leave that vague squee or uselessly quote back favorite lines.