Our company has used the email service from Technology Land for over the last 3 years.
The solution runs very fast with high reliability. Also, it works on many platforms from web-based to mobile, covering all devices used in our company. We love the admin panel that enables us to manipulate the whole accounts and functionality.
So far, the support of this company is very impressive no matter how big or small the incident is. Somehow, better than the support from big name company.
If you are looking for a corporate email solution, I would definitely recommend Technology Land.