Using a "quick connect" terminal for IEC inlet or just soldering the wires?
Using slide-on terminals (we call them by the trade name "Fast-On") is common and reliable.  The only time I've ever run into problems with when the terminals were of poor quality.  The 3M terminals that you have selected should be just fine.

Something that is important to note is that the quality of the crimp used to apply the terminal to the wire affects reliability.  3M will specify the appropriate tools that are recommended and you will think that they are expensive.  And they are.  But they will guarantee you a reliable crimp.

You can purchase generic crimp tools that are inexpensive.  Some of these will do a good job but many will not.

Bottom line: if you have access to the proper crimp tools, the 3M connectors you linked to will work well for you.  If you don't have access to good crimp tools, better to be safe and simply solder your wires to those terminals.  Insulating sleeving (heatshrink, Hellermann sleeve, etc) is usually optional.