Moving from Canon to Pentax has been a good decision for me till now.
Used to love my canon 50mm , and used it a lot. Served me great to take photos of babies in low light.
But from the first few shoots I did with Pentax, I have found that the FA is a higher quality lens than that of Canon.
Mind you, my canon body, 400d was 5 years older than the new k30.
The sessor in K30 has better dynamic range, and inbuilt image stabilization.
So better image quality cannot be necessarily be attributed 100% to the lens itself.
So here it is, I find the pentax has slightly more contrast than the Canon.
The sharpness is little better, and colors come out really nice.
Slightly warmish probably, but that works for the portraits.
Posting some pictures of my little daughter Anushka.
The first one with blue flowers is shot with Canon
The one below in fall colors is the pentax one.