This game is a blast to play. Good survival-horror, a crazily-effective take on the concept of open-world gaming, and a really captivating story. Yes, some parts of the plot are a bit cheesy, but even the best Resident Evil games have their fair amount of cheese.
I played the original Evil Within despite some murky reviews, and also despite being genuinely terrified by the premise. The story presented in the original was intriguing until the realization that it was getting very convoluted with no chance of gaining clarity. The controls weren't too bad once I adjusted, but they were somewhat clunky. Either way, it was Survival-horror, terrifying in spots, and the boss fights were very engaging.
Though many fans of the OG will not agree, the mechanics and story are much better in the Evil Within 2. It is still very much a survival-horror when played on the moderate-to-higher difficulties, and many elements are absolutely chilling. However, the scares and atmosphere aren't quite on par with the first (but they are much better than a lot of the schlock that's been pushed out in the past several years). Overall, though, I feel that the Evil Within 2 is the better game, and really improved a lot of the hang-ups of the first entry.
Lastly, as the question comes up a lot - no, you don't have to play through the first to enjoy this one. This game does a nice job of incorporating a recap of the first game and includes it in a way that won't make people who missed the first one feel lost. If anything, play through this one first then pick up the first as a sort of prequel. However, I will say that a major plot-point of the first game will be spoiled by playing this one first.