Well...My first toy ever (insertable vibrator) was hard plastic, I didn't enjoy it very much, and I've never tried jelly and don't plan on it due to its being unhygienic. I do have a glass g-spot toy that I adore. So I'd have to say glass.
I usually prefer plastics for cleanliness, however I have been finding out that there are other materials that feel great. Which ones do you prefer and why?
They are ALL so different. I have some of each. Still (sorry) love my Jelly's, but have some favorites in METAL (cool, slick, hefty), glass (super slick with lube...no friction, just "full", and even wood, sensual and warm.