I've been using vRealize for two years.

I've been using the solution for about half a year. 

I've been using the solution for about eight months.

I don't know exactly how long I have been using this solution.

We have been using vRealize Business for Cloud for the past four years.

I have been working with the product for three years. 

In total, I have been using vRealize for probably 12 years. Obviously it was not the cloud version for that entire time. I have been using the cloud version for the past few years.