I've cut a fair bit of crown, and it can all be done with a mitre box and a back saw...but it is much faster to do it with a 12" compound miter for small and moderate work and a 10" or 12" slider for the wider stuff. A Collins coping foot on a good barrel-grip jig saw is your buddy, as is medium CA and a good accelerator (GluBoost rocks) on paint-grade work. The newer sliders/gliders are very stiff and address the issues seen in the first generation of Makita LS sliders, but they do take up a lot more room than a 12" compound. If space is an issue, and you are not working crown stock over 7", fixed compound miter saws are likely the best compromise. For wider crown stock as used for large rooms, or if working a complex roof framing job, the bigger sliders make things easier.