I recently bought a Shield 40 after checking one out at the LGS and really liking the way it felt.  I was using a Taurus TCP .380 for CC because the Glock 22 I had was hard for me to hide.  I'm not familiar with the M&P models and I understand the Shield is a different breed being a single stack.  I've read a lot on this site regarding the AR platform, but recently I've realized how much more is on here.   I plan on working on my trigger a little using the info found on this site.  I've learned quite a bit about the M&P and now I'm tempted to see how the others compare to the Glock I'm use to.  

Anyways, thanks for all the good information.

Shield is a great little pistol. I only owned one in 9mm. Sold it a few months back to "upgrade" to an M&Pc, but it's on my list to reacquire. Congrats!

If you shoot it and feel the trigger leaves a little to be desired (I don't have a problem with the stock trigger), you can install an Apex kit. It makes a difference.