Thin is in.
The thinner the holster, the easier it carries. Some rigs have too much bulk. As it is, a 220 isn't a slim gun and you'll have to open your belt a notch or two to accommodate this fine pistol. Avoid any holster that uses a clip you might find on an eyeglass case. Clip must lock onto you belt so that the rig doesn't ride up and out.
Int'l Assoc. of Law Enforcement Firearms Instructors