For a while, my ISP was using some sort of transparent proxy cache, which for some reason tended to stall HTTP connections (stuck in SYN-SENT IIRC). There were days when the only sites I could access were the ones using HTTPS, since the transparent proxy cache didn't touch them.

The most advertised gain from using TLS is security, but to me an equally important gain is not having to deal with broken middleboxes.