On bottom of the case there is an interesting feature. A small plastic box is a perfect place to put all the unneeded PSU cables into. No need to struggle with them and try to hide them between the motherboard trail and backpanel that way. I’d like to see such feature in more cases as it is simple to make and doesn’t cost that much.
HAF XM has a nice cable management system. The Motherboard trail has a couple cables in so you can easily put all the cables between the backwall and motherboard trail. This way the cables does not block the airflow within the case and it also affects how the interior of your case looks.
All extension cards are held in case with thumbscrews. Coolermaster has clearly made the HAF XM as toolless as possible and this is a positive thing. The less you have to use screwdriver or tools when assembling your case, the easier it is to add extension cards, hard disks and ODD:s afterwards.