It depends on how you work together as a team to be honest. I was equally concerned (about all sorts of things!) when my DH announced he wanted to join the police, but for us it works.
The shifts can be horrible, and they can change on a regular basis...I think DH has had about six different shift patterns in as many years. At the moment he works two earlies, two lates, two nights then has four rest days. It makes regular routines difficult. Earlies could be 7am-4pm/6pm, lates could range from 3pm-11pm to 5pm-4am (yes, really!) an nights could mean starting at 11pm and coming in at 7am.
If he is good at sleeping through anything it can work (my DH luckily is) otherwise it's really hard to keep the kids quiet while he's in bed, and you can't hoover or anything like that! He usually finishes on time, or is able to let me know if he will be late, so in many ways it's more convenient, as he is able to pick the kids up sometimes, be in for deliveries on his rest days, get DIY/housework done while we're all out the way during the week, etc.
It does mean we sometimes feel like ships that pass in the night, as he's headed off to work before I come in, and occasionally I moan that I feel like a single parent, but a lot depends on how you work together as a couple/family...communication is key!