Since you are already talking about it without even moving to Android yet def use the 15 day remorse period. Some people can't be without it and some iPhone users don't care.
My brother in law that had a couple iPhones dating back to the iPhone 4 and just had the 5S the last 2 years. He made the switch to Android and got a Galaxy S6 3 weeks ago and loves the thing. I asked him if he missed iMessage and he said. "I couldn't care less about that stuff". "I have a phone that can do so much more ". I'm not paying $400-$500 for an Apple phone on contract. Got his S6 for $99. All depends on what you want.
I for one thought losing iMessage was going to be a massive deal to me. I had my days no doubt. I don't care about it now though because I look at my Note 5 and say "Wow".