Great service, great sleep, so-so area
Disclaimer: I am a fan of W hotels.
As I used to live in Los Angeles, I am very familiar with the area. Situated across the street from the Pantages theater, is it directly above a subway (yes, LA has a subway) station, and steps away from the Hollywood and Vine intersection, Capital Records building, and within blocks of many famous Hollywood landmarks. It is a bit farther from the Hollywood and Highland complex, but some would still consider it "walking" distance depending on how much you like walking. 
As for the hotel itself, it's a great modern addition to the area. While the area around the hotel doesn't feel super safe at night, there are plenty of eateries and bars in the area that ensure constant foot traffic. The rooms were very typically W, with all the amenities and modern design that I've come to expect. The free wi-fi was a great bonus, and the rooftop pool (that shares a space with Drais for daytime pool parties on weekends) was nice. It felt more "Vegas" and is a nice place to relax on a warm day. I was not there when it was busy so can not speak to the types of people that hang out there or how it is when it's busy.
The service was excellent. Checking in, I was able to request a late checkout and was accommodated beyond expectation. All the staff always was eager to help and seemed very helpful. Calling down for the car from valet was easy, and the car was ready to go within minutes.
Overall, the experience was great. I would go back. As with all W's, it can be pricey and may not be worth it to all, but if you're looking to splurge and want to be in the center of it all, steps from a hot nightclub, have a great pool, and like modern design, the W Hollywood is a great place to stay.