Another vote for MM! They have some great coasters! Not to make it more confusing, but Knott's also has come great coasters as well if you're looking for thrills. Xcelerator, Silver Bullet, La Revolucion, Supreme Scream, and Sierra Sidewinder are all great! And of the 3, KBF is the closest to DLR. I personally hate the drive to both MM and Universal.
I know some people here on the boards hate KBF, especially if compared to DLR, but you can't compare anything to Disney. And on it's own, Knotts is great. You get thrill rides as well as some of the classics.
Add you can usually get a discount to KBF. Currently you can get into KBF for only 28.99 with a coupon from Burger King. "Pick up money saving coupons on adult tickets at participating So. Cal. Burger King restaurants. With coupon Adults are just $28.99 and kids ages 3-11 and seniors 62+ are just $19.99!"
Have a great time, no matter what you decide.