Metal laser marking machine diverse market price

I want to buy a metal laser marking machine, searched online, too many brands, more than USD10000 for expensive one, more than USD4000 for cheap one, what difference does it have?
Mainly to see what materials you want to mark and what effect you want, because there are many types. For example, if you want to mark a tube, especially the inner wall inside the tube, then you must use rotary or 3D marking, if it is marked on flat,like a cell phone case, then it won't cost too much for the ordinary 20w desktop fiber laser! There are also under USD4000 in China market, please don’t buy it, because honestly they will use not good quality parts, like scanhead, power supply, etc, quality is not guaranteed! Also price decide the warranty and aftersales, if very low price, the warranty and aftersales service is not good and in time.