While I think Onepass is a great program, it all depends on your flying pattern. All of Continental's flights out of Los Angeles will go to one of three hubs; Houston, Newark, or Cleveland, OR Honolulu. For shorter flights, Continental isn't the best airline of choice.
Onepass is a member of Skyteam, Alaska Airlines, and a select other partners. Within the US, you can accrue miles on Alaska, Delta, and Northwest, but amongst them, there is no or limited service for flights within California. So if the route pattern is what you look for, I'd choose another.
Getting award travel booked is also difficult. Some of us consider it, "Nonepass" as they have experienced difficulty in finding saver space. While I don't disagree with that statement, it can be difficult if you are not flexible on your travel dates.
If your flying habit is frequent, Onepass might be a program for you. Once you attain an elite status, flying 25,000 miles or more within the program year, you will attain status. Members of high frequent flyer status is rewarded with complimentary upgrade for flights within the domestic 48 states. With great choice of meals on domestic first class, and excellent Continental flights, they really knows how to treat its customers well.
Finally, you had mentioned that you are pre-approved for the Chase credit card. I believe Continental is offering 5% discount for booking with this credit card. If that is a sufficient benefit for you, maybe it might be worth a try.
Jiburi