I don't hate it necessarily, but "seizure" is by far the more precise and medically correct word, and more useful in communication much of the time (unless you're dealing with someone for whom "seizure" has too many syllables to enter their vocabulary or something, in which case I personally would rather not discuss the matter with them in the first place because of all the other things that wouldn't be entering their heads either).
The word "fit" is associated with quite a few things that have nothing at all to do with seizures (even though they may resemble them to the uninitiated) as people have pointed out here, and would be commonly used for what are more technically called psychogenic seizures too. This can easily mean that in many people's minds (especially of people who are not well educated about what a seizure actually is) the very use of the word carries implications against the self-control, mental stability, etc, of the person who is having the seizures. This kind of prejudice is definitely not something most Epilepsy sufferers need; they get more than they deserve already.
It seems pretty important to me to insist that society is pushed to recognise that seizure activity is the result of organic brain disfunction, not weak-mindedness, etc, on the part of the suferer; and I honestly think that the widespread use of imprecise terms such as "fit" simply confuse the issue and make it harder to educate people properly. "Seizure," by contrast, is a medically correct, neutrally descriptive term that carries none of the same negative connotations. It's rather broad as well, but the process of explaining what the term can apply to is part of the process of education I suppose - it seems much better than allowing people to think THEY know what a "fit" is already, when in fact they don't have a clue what you're talking about.