What's a decent Android app for sending texts that actually works, even when I'm out on a job site with spotty service?

Look, I need an app that sends texts, plain and simple. No BS. This 'Messages' app, it's alright. It's not fancy, but it's actually rugged enough to handle getting banged around in my truck. I've dropped my phone a couple times already and the app still works fine, so that's a plus. Sometimes the service out on the construction site is garbage, but this thing seems to hold onto messages and send 'em when it can. It's built like a brick house, I guess. The battery drain ain't too bad either, which is always a concern when you're out all day. The tutorial is useless, but once you figure it out, it's straightforward. Rain doesn't stop it from working either, which is a bonus when you're working outside in Denver. Gets the job done, which is all I care about.