dben002 - I beg to differ, the Glock has better sights IMHO for many people. Especially older people due to the large, easy to aquire white "U" rear and white front dot. G23's are usually pretty good with recoil, as good as the M&P's and the triggers are better "out of the box". As for feeding issues, I have quite a few Glock pistols and have had minimal issues (operator error). While I do like my Shield 9mm, M&P FS9mm, and M&P 22 compact very much I do agree with earlier post regarding the Glock being one of the best polymer guns being produced.

My Shield has had a few feeding issues and does tend to "guppy bulge" the cases a bit with hotter rounds but so do earlier Glocks. While the stock trigger is not bad by any means, I did have to go with an Apex to get an acceptable (to me) trigger. I also changed the sights to TFX Pro's to get a better sight picture for my old eyes. It is all relative to the user - each likes something a little different and one gun does not "fit all". IMHO the M&P series are very good pistols and I carry one daily.

OP - I would keep the Glock, then go with the M&P 45c which should be a nice fit for you since you like the Shield 45. I would also look for a nice 1911 but don't go too cheap. I would at least go with a Ruger 1911 LWT Commander or if you can save a little, go for a Springfield Range Officer or Kimber Commander size. Or, you could always go 1911 style but chambered for 9mm, the EMP4 is a great shooter... :-)