It wasn't that bad actually. Lust (and pretty much everything) was pretty spot on for squeezing 40 episodes into about 2 hours. I mean it had its flaws, but it was a pretty faithful adaption, I personally enjoyed it. The woman who played Lust did a great job, I was impressed.
I only watched the first 15 mins with my partner. We're both huge 팬 of the series so the first impression was lackluster. It's not bad enough for me to ditch entirely, I'll go back and watch the rest sometime.