I have the r10, the ultra, and the hw.
The hw is faultless, just as everyone says, it certainly does the job, but I found it just wasn't balanced right for me, front heavy, not a heavy gun, but unbalanced, so I swapped the air tube for the a@m lightweight, and the silencer, sorted the balance right out, lost some weight, and improved shot count.
The r10, it's been perfect out the box and never missed a beat, good balance, good shot count, accurate as anything, and reliable, I've never messed with it as have no need, but, watch what scope it's fitted with as I found the good scopes m