@Asset
Honestly, it's almost always up to personal taste. LNs are supposed to be refined versions of the WN where the author changes things up and polish the original WN. What I do find, however, is that all too often do authors remove the wrong things and ruins what made the novel great in the first place. Just one example is "the rising of the shield hero". The LN butchered it completely in my opinion, it was quite decent in the WN format but nigh unreadable in the LN format, especially since you knew how things went originally. Others might disagree though.
If I had the choice, I would almost always go with the LN of any given novel unless there has been harsh criticism against it, because it IS a polished version of the novel. But the LN comes later and also tends to be licensed. Honestly I wish I could just read the raws already but I'm probably a year away of japanese studies for that.