Mothers in general are a bit of a mystery to me - I don't really have much of a relationship with my own, I have a foster mother who drives me a little bit insane most of the time and a MIL who is I get on well with and love but find her a bit hard work sometimes.
With my mum she expects me to be independent (which I pretty much have been since 16) but to add a cultural twist she expects me to do all the work for our relationship eg I should call her and I should go to see her. My parents have never been to my house, we've lived here for nearly 3 years and they have no idea - I don't think they even know my address. I really don't agree with their attitude, culture or no culture so I just said if you want me you know where I am so either you call or I will do it when I get round to it. they still haven't learnt but it doesn't really affect me to be honest.
With my foster mother all I get is moaning or whining from her - she has a very dependent personality which I just can't cope with. I find it hard to deal with her as she basically wont look after herself and refuses to be a grown up and get on with her life. She makes very poor decisions, is bad with money and doesnt take care of her health but expects everyone to baby her and do it for her. Well I love her but she does need to get a grip of herself but I tell her thats my opinion so she knows where I stand.
My MIL is generally my friend - we laugh and joke together and I complain about DH to her because no one understands a mans 'little ways' like his mother but luckily she isn't the type to think her son walks on water so we do have a giggle about things. Our main problem is the fact im so independent and she wants to be helpful. I have no experience of parents who do lots for you so found it really hard to deal with her and found her quite interfering at first. When DH was away with work we were sort of thrown together and so had to work it out - I've come to the realisation that she actually enjoys being called upon to do things that most people hate ie cleaning and laundry. But now I know I find things for her to do and it makes her happy to feel that she is helping and me happy to know that things aren't strained between us.
As for the baby dynamic - I think everyone is well meaning no matter which mother they are but I think as many women 'tend' to be closer to their own mothers MILs just feel worried that they will be second best granny to the kids. To be fair I think my MIL will have the best relationship with my DC out of all my mothers because she will make the most effort to be here doing things plus her housework is immaculate so I know who to call if I ever can't be bothered with it once the baby comes!! 
I think the MIL-DIL thing is hard but no harder than any of my other daughter-mother relationships. I'm a very forthright person and if I dont like something or I'm not happy I just tell them - I dont bother going through a 3rd party. Sometimes it hurts their feelings as they usually are just trying to help but i feel it's better to be honest than spend forever feeling resentful over things!!
Now the scary thing is I'm expecting a daughter in a matter of weeks and I keep telling DH that I have no idea how I'm going to cope - practically and financially all is fine but as I have no experience of what a 'normal, happy and reciprocal' relationship with a mother looks like I dread to think what she is going to think of me......I'm just praying she doesn't want to leave home at age 11 like I did!!! 