I ride all but 2 big thrill rides at Universal but do avoid the following due to extremely wild motion effects: Dr. Doom's Fearfall and Hollywood Rip Ride Rockit. In fact, I've never ridden them even once. I have riddden and would ride again any of the other big rides there. Overall, Universal rides are probably more jarring than all Disney rides except perhaps Rock 'n Roller coaster which I don't really like at all but will ride if DS wants me to.
Here's a quick
link to someone's ranking and descriptions of the "thrill rides" at Universal Orlando.
However, I think both of the Harry Potter big rides are fine for just about everyone: "Forbidden Journey" and "Escape From Gringotts". I really like the Escape From Gringotts ride most of all the Universal attractions. The que alone is fantastic and the ride excellent. Overall, I think Universal does a great job with their rides and technological effects, better than Disney in fact.
Give their big rides a try and see what you think!