IMO it depends on how helpful they will actually be, as opposed to expecting you to hostess for them.
I had MIL stay with me for 2m - 2w prior to DS' birth and 6w after (she came over from Australia though so a bit different!)
It was not much problem - the 2w prior to the birth were harder because I was overdue, crotchety, didn't want to go out much yet DH seemed to think I should be entertaining his ma. She didn't, I hasten to add! Plus she had SILs to go and see.
Afterwards it was mostly really good that she was there - she did washing, washing up, kept the kitchen in order and basically kept the house in order. DH doesn't "understand" housework , probably cos his mum has always done it for him! We missed her when she left - suddenly all this background stuff needed doing again and it was a fight to get DH to realise he had to help pick up the slack as I still had a very small baby to deal with.
As far as bonding went, it wasn't a problem. DS was a very poor feeder - I spent a lot of time in bed with him because he could only feed lying next to me for the first few weeks until he had his tonguetie snipped. So we bonded fine - DH had no problems bonding with DS when I had to go out for my hospital appts (although MIL probably did most of the work!)
MIL is not an intrusive person - and she always pitches in, she would be in agonies if told to do nothing. So - it depends on their personalities and whether they would actually help or just get in the way and create more work.