I tried this curved curtain rod at a hotel we stayed at. I remember seeing it at Bed Bath and Beyond. It gives your bath tub extra room while you shower and you can use a regular shower curtain with it. No special size curtain is needed.
I don't know about you, but when I shampoo my hair I lift my elbows up and out to the side. I usually end up touching the shower curtain with my elbows. In a hotel, the less you touch surfaces the better! I loved this shower curtain rod because it gave me so much extra space from the middle of the shower curtain to the top. Not once did my elbow touch the curtain in the hotel.
This would be great for using with an oval shaped tub. It extends your curtain out 6 inches in the middle and then curves back in to make sure there is no water leaking out from the edges. I love the look and extra room this Crescent Rod gave me in the shower. I would highly recommend this and I think all hotels should have them too!