I should say that I was working with birds that were either injured and couldn't be released into the wild, or part of breeding programs. So some were worse than their "wild" counterparts and others were more mellow.
I think each individual bird has it's own personality. The peregrine I worked with the most was really relaxed, however I also worked with a kestrel that was completely batshit. They're wild animals so they all have the potential to injure.
We had a couple of red tail hawks you really had to be careful with because they would sometimes attack out of the blue. But there was a broad shouldered hawk that was very well behaved. Both of those birds are similar in size. However, bald eagles and golden eagles were the absolute worst. Not only are they huge birds, but they have this almost malicious intent to injure you.
I think it really depends not only on the individual bird, but also how much contact is has with people, reaction to crowds, and prey drive. Larger birds are more difficult to handle, mostly because of their size and strength (which they don't really have an idea of). For example, the great horned owl can exert 350 lbs per square inch of pressure using it's talons. So it could put holes in your arm without being aware of what it's doing, should it become stressed.