What are some alternatives?
When comparing Text United and Transifex, you can also consider the following products
Crowdin - Localize your product in a seamless way
Phrase.com - Phrase is a translation management system where localization teams come together to release translations faster and easier than ever before.
POEditor - The translation and localization management platform that's easy to use *and* affordable!
OneSky - Full Stack Localization Solution
Lokalise - Localization tool for software developers. Web-based collaborative multi-platform editor, API/CLI, numerous plugins, iOS and Android SDK.
Smartling - Website localization & translation