West Derby is a LOVELY AREA!!! I honestly cannot think why someone would say it is not nice!
I live in West Derby... I am not from Liverpool but have been here for 7 years now and I can honestly say that living in Liverpool is the happiest I have ever been.
It's a quiet area with good amenities and more importantly nice, normal people trying to live quiet, happy lives.
The reason it is cheaper than Crosby is simply that Crosby is one of the most expensive places in the whole of the UK to live. Whereas Liverpool is one of the cheapest.
If you can afford to buy in Croby and that's really where you want your children to go to school then I would recommend you buy in Crosby.
If you are looking for somewhere in North Liverpool as a cheaper alternative to Crosby then West Derby is a great comprimise. It's a lovely area in my opinion, one of the nicest areas in Liverpool. My husband's family are from there.
My dad lives on the Wirral and I would again say if you can afford the nicest areas like Caldy, Heswall, Thornton Hough it's a great place to live... If you can only afford Birkenhead then I would stick to Liverpool.
Friends of mine live in South Liverpool and their middle daughter goes to a school in Croby that have a school bus. It picks up in South Liverpool then North Liverpool then onto Crosby. I think she has to get the bus at about 7am(ish) but at least it's only 1 journey. If you want them to use the train the Train links are much better in South Liverpool. It's mainly buses in North Liverpool.
PLEASE DO FEEL FRE TO GET IN TOUCH IF I CAN HELP YOU AT ALL!
Good Luck with your move.