AFAIK mdadm has been stable for years (one of the reasons why I prefer software raid to hardware raid). As long as you boot into anything resembling a recent Linux kernel along with a userspace with mdadm support, you should be fine.
If in doubt, boot from a live-cd/usb and see if you can mount your drives ok.
If in doubt, boot from a live-cd/usb and see if you can mount your drives ok.