HA between rSeries tenant and iSeries appliance.

According to F5 documentation, the BIG-IP system supports either homogeneous or heterogeneous hardware platforms within a device group. I want to confirm if anyone has tried to put rSeries tenants and iSeries appliances in the same cluster? Obviously, I understand they will need to be on same version and of course vlans will be same on both. If you have tried this before, what were your challenges and how did you overcome them?

I am considering this approach because it makes migration easier and seamless.