I have stayed at this Hilton Gardens location before, entirely because of it's proximity to Magic Mountain and they have a free shuttle to the park. It is a bit on the pricey side for this type of hotel. In the summer, it was about $150/night with taxes and I have a government discount. I didn't really mind paying a little extra for the convenient location, but if you are more money conscious, there might be lower prices in the area.
The room was clean and well laid out. There was a flat screen TV and a mini fridge. We used the hot tub, but not the pool, after walking all day. Free wi-fi was helpful, since all we brought were smart phones and it cut down on our data usage.
There is free parking and they have a good size parking lot, easy to access from a couple of different ways. There are a lot of casual dining places and stores within a pretty easy drive, too.
The front desk seems to get very busy (I went to the lobby for a couple of things), but after waiting a few minutes, everyone was very polite and helpful. They also had free cookies and water with melon in it at the front desk, which was a classy, refreshing little deal.
We did not eat on the premises, but they have a restaurant and I heard other guests on the shuttle saying it was good.
Having a shuttle is great. At least it saves you from paying to park and if you want to drink a few adult beverages in the afternoon and return the park on a weekend evening, you can. Plus, if you don't want to wait for the shuttle on your return, it's about a 1/4 mile walk down the hill. No sidewalks, but there is a grass median most of the way and just a little bit of walking on the dirt. There is also a paved road about half way down that leads to the back part of the hotel property, but there is no cross walk there for the busy Old Road. My wife and I have stayed at this hotel twice (6 nights total) and we have walked down the hill three times because the shuttle would have been 30 or 45 minutes. It comes fairly quickly, but we didn't mind the walk down.
On a side note, it was cloudy and rained in LA (not really up in Santa Clarita) and the park wasn't that busy on our stay. We managed to ride every coaster we wanted (skipped some smaller or older ones), including a 20 minute wait to get on Full Throttle and about a 30 minute wait for X2.
I do recommend this hotel, primarily for it's convenient location and shuttle, but everything else you want in a hotel is very nice, as well.