Here's some things to consider:
SIG Sauer P228
Pro: Excellent DA and SA pulls, very accurate, reliable
Con: Prone to surface rust, must be kept well lubed, DA to SA takes practice, complicated mechanism requiring trained armourer
Glock M19:
Pro: consistent trigger pull, lower bore axis, lighter, less sharp edges, needs very little lube, you can learn to completely diassemble it in a few minutes
Con: trigger pull takes getting used to, will retain less of its value (this may not be an issue since you're dealing with used pistols)
Fire both and choose what works best for you. I love the P228 but prefer the M19 as a defensive tool.
------------------
So many pistols, so little money.