Yes usually SRS based is in good RF while PMI based is in bad RF.
This is decided based on UL SINR.
You can see a plot here:
Live Draw - online drawing board - Draw, Share, Collaborate! how beamforming is made .
But it is better explained on Sharetechnote here:
The picture above is most important to understand beamforming precoding and everything!
Also one need to understand that it all depends on multipaths and air interface matrix.
Otherwise there would be MIMO 4x4 everywhere.
But it is the air interface matrix that limits the rank.