Basically:
- 5W laser is mainly used for engraving or very fine inlays, cutting with this will only get you through 5mm stock at most, use it only if you have thin stock that needs a clean cut without fuzzies
- Drag knife is for very thin material like paper, vinyl, foam and such
- For everything else, use the router with an appropriate bit
One thing I’d like to try someday though is a “drag bit”, this seems to be somewhere between all three of those… using the spindle without spinning it to precisely etch a surface