Although I didn't use a walker, all my research (including baby physio) says the aren't bad for them. The biggest danger is siblings pushing them around or unstable floors (stairs etc). Another issue is parents mis-using them - basically leaving their babies in them constantly. I suppose its an easy temptation. After DH and I chatted about it, we really couldn't come up with good enough reasons why to get one. I just didn't like the idea, felt like I was being lazy. I only have the one baby and had the first year off work - so have plenty of time to do all the chores and look after DD.
DD is 3yr 8 months - DS is 6 months