Some of my iMessage messages take 30+ seconds just to send and I'm not sure why. At first I thought it way maybe b/c my data connection was bad. But I have the same issue at time on a very strong Wifi connection. This also never happens when using third party messengers like Whatsapp. So what gives with iMessage? I should also mention that I had the same issue on my iPhone 4 w/ iOS 5 installed so I know it's not an issue with my iPhone 4S.