3rd party folio and pen

looking to pick up a remarkable 2 and wanted some advice on the 3rd party products. Ive seen a few times that people have issues with the magnetic folios that are put out by 3rd party companies having a tendency to mess with the line accuracy. how common is that and are there any fixes if the issue crops up?

also looking for a link to 3rd party pen that also has an eraser. if someone could share a link to one i would be much appreciated.