I went through the roughly the same dilemma last week.
I had two choices: One, a strictly clerical position in ER, CCU, ICU, etc., with some possibility of observation.
Or two, a position at the hospital's therapy center where I was promised little to no clerical roles.
I went with the therapy center because I've already spent a ton of time as a volunteer in ER and felt a clerical role wouldn't benefit me. Basically, go with Popoy's advice: do it if you think you really will gain from it, aside from a impressive looking bullet on your resume.
Then again, I'm still youngster, so just go with what you feel is right for you.
PS: Off topic, but I've spent a little time in ICU and found it very depressing. It's perhaps a reflection of my youth, but I enjoyed other floors much more.