My personal take (I'm in a Clinical Ph.D. program) is to be honest about your therapy experiences, but only if you feel comfortable. The way I see it, if I am honest and they perceive it negatively, I probably would not have wanted to work with this person anyway. I makes me want to vomit when I think about people in our field who would stigmatize or discriminate against someone who would seek help.
I'm not sure what your interview is for (for grad school? for internship?), but generally, here is how I would handle that question. I'd say something along the lines of: 1) yes, I have been in therapy. 2) I had a range of experiences, some were more helpful and others, less so. 3) it gave me some experience for what it is like to be in therapy, to have someone listen, and to understand the value of a good therapeutic relationship with my therapist, and 4) while this was my experience, I acknowledge that this may not generalize to all people in all situations; it is a helpful starting point but is never an assumption for what someone else's experience is like.
FWIW, I think personal therapy experience can be useful in clinical settings and can help clients feel a greater connection with me. Just my two cents, but I'm sure there others who would disagree with me. Hope it helps!