Linkshare is one of the fastest growing affiliate programs on the internet. They have a lot of big name companies that participate with them, and they seem to be the provider of choice if a company leaves one of the other affiliate programs.
When I first signed up with them they didn't have a lot of advertisers. Probably the biggest name they had initially was Skymall, which are the people that have the magazines on airlines with all the cool stuff. Now they boast companies such as Barnes & Noble, Microsoft Store, Buy.com and Fiji Water.
They offer advertisers in almost any realm you might search for including airlines, hotels, gifts, jewelry and all sorts of other items. The only problem I have if I have to compare them with Commission Junction is that there's no template associated with them. In other words, you'll have to figure out how you want your advertisements to show. However, most of their advertisers will pay you at a rate that competes well with CJ. However, as full disclosure, I've yet to make enough money to tell you how easy it is to get paid. I can say that I've been credited with every sale I know I've made through them, so I haven't had a customer service issue to deal with yet.
Linkshare also offers its own referral program, but you only get paid $1.50 per referral if that referral makes a sale within the first 30 days. That kind of stinks, but it is what it is. Still, it offers something different to look at for both big name advertisers and smaller companies that have a lot to offer.