They're okay. Our closest airport is Newark, so we almost always end up flying Continental. Honestly, we flew quite a bit last year and we did have all good experiences with Continental. I think every flight was on time.
The only thing I really dislike about Continental is that the seats are tiny and the legroom is teeny. I swear their seats are vastly more uncomfortable than anyone else's. We flew to London two years ago and I felt like I was traveling in steerage. Miserable.
BTW, if you ever shop at ShopRite (the grocery chain), go to ShopRite's website and sign up for the free OnePass miles program. When you use your ShopRite loyalty card, you automatically get OnePass miles. So that's a good thing about Continental right there!