I've never used eHarmony, PoF, or OkCupid, but I'm considering them, and from what I'm reading here it sounds like eHarmony might be a better fit for someone that isn't quite as comfortable with initiating contact via a random message, because it forces you to jump through all those hoops to even communicate with someone. It is almost like they have created a reason for women (or men, but we all know I really mean women) to actually pay attention to you because they aren't being inundated with hundreds of messages a day. If you're one of their limited number of matches, they almost have to pay at least a little attention.
At least, that's the way it sounds to me, not having used it. Personally I don't know which is best for me, because I'm older and not a Keg Lannister (and I'm not really looking to get married or anything either, which seems more eHarmony's thing), but I can see where the restrictive nature of eHarmony could work to a guy's advantage at times. I can also see where it would be completely frustrating too.