I have used this solution for three years.

I have been using SonicWall Email Security for approximately two years.

I've been using this solution for a year. 

We have been using SonicWall Email Security for around three years.

We have been using the solution for more than three years now.

We have been using SonicWall Email Security for more than five years.

We have been SonicWall Email Security for four to five years.

I have been using SonicWall Email Security for approximately seven years.

The TZ Series is deployed on the cloud.

I use version 3300.