Do you mean the game itself is so highly praised or the new mod? I don't believe the mod is really all that highly praised. There's probably as many people who don't like it as there are who do. It's not for everyone.
If you haven't beaten the game normally yet, I recommend you do that first. Then you can try out the mod on a second playthrough. If you're not the sort of person who plays games more than once, then it's really up to you whether or not to use the mod.
Personally I love the mod. Combat feels much better to me overall, and seems more genuinely how a Witcher in general would do combat.