“Their service has more bells and whistles, but mine is much simpler and quicker to use.”
You just answered your own question. You must focus your marketing on “simpler and quicker” to the exclusion of everything else. (Either “simpler” or “quicker” would be even better, focusing on “one” thing.)
Jack Trout, in “Differentiate of Die,” says it much better than me:
“The best way to really enter minds that hate complexity and confusion is to oversimplify your message. The lesson here is not to try to tell your entire story. Just focus on one powerful differentiating idea and drive it into the mind. That sudden hunch, that creative leap of the mind that “sees” in a flash how to solve a problem in a simple way, is something quite different from general intelligence. If there’s any trick to finding that simple set of words, it’s one of being ruthless about how you edit the story you want to tell. Anything that others could claim just as well as you can, eliminate. Anything that requires a complex analysis to prove, forget. Anything that doesn’t fit with your customers’ perceptions, avoid.”