I just went on Wednesday. I have a Gold Season Pass, which comes with free parking and I got my buddy in for $10 with season pass perks. Admittedly, I am a roller coaster enthusiast. I have operated multiple rides at 3 parks in Southern California, and was a roller coaster mechanic for about 2 years. Roller coasters and Angels baseball are pretty much the only things I nerd out about.
Don't believe the knuckleheads in this thread, the park no longer has the gangster trouble making hooplah reputation it became popular for a decade or 2 ago. Some people love living in the past. The place ain't Disneyland, but it's much better than what it used to be. Ride operators at this park, however, have much to be desired. Which is why if you wanna ride a bunch of coasters, the Flash Pass may be your friend. Keep in mind, Magic Mountain has some pretty extreme rides, so maybe you don't need to go on everything to have a good time.
The Flash Pass is kind of worth it, if you're not going to visit in a long time after this trip, or if you wanna get on everything, and are willing to pay up the ass. Best thing to do is go to the park early, see how the crowds are accumulating, then decide whether or not you want to wait in lines or pay to cut everyone off. Looks like the platinum is $125 per person (after paying for a ticket to get in), which will get you both 1 line cutting ride on Twisted Colossus, Full Throttle, and Superman. Then you get to cut in line for everything else unlimited besides X2, which you can actually pay $20 per person to cut in that line as well. The gold is $70 per person. I've done the gold, waited for X2, Full Throttle and Superman and got on everything. Cutting in line on every ride is overrated IMO. I'd suggest the Gold, get on all those rides, then actually wait for the other ones you didn't pay to cut in line for. Waiting in line is fun, especially with a girlfriend.
X2 generally has an afternoon "lull" where waits between 3pm and 6pm are between 30-60 minutes.
https://www.sixflags.com/magicmountain/store/flash-pass
If you can go during the week, that's your best chance to get on as many rides as possible.
X2, Twisted Colossus and Tatsu are my favorites there. Any other questions? Ask and I could probably give you some pretty accurate answers.