Simple, modern & fast web-based email client. Modest system requirements, decent performance, simple installation and upgrade, no database required. All these make RainLoop Webmail a perfect choice for your email solution.
Used many solutions, but RainLoop is the best. For now, it is pretty fast, usually even faster than Gmail. Very easy installation process which took me 5 mins. The design is really cool. I use it for a personal email server and really happy.