10mm
Jspy,
Look at it this way...the 10 mm. teaches you to bear down and use good follow through...That way your .45 feels softer when you shoot it.
The only thing, honestly, is that I had to practice a lot more to bring the 10mm down to bear on target for follow up shots, but I certainly wish I had gotten the Delta Elite a while back.
Really, a positive response learned was that I am much quicker at my follow up shot on my .45.
Other than that, it's just a little louder, little more recoil.