I adore both.
Adelaide is gorgeous- I like
Addie, but
Adele is nice too, another idea is
Della. And
Matilda is lovely, very Aussie. I don't know if I'd have the guts to use
Adelaide (I live in Australia) but its in my Top 10.
Matilda would be there too if it wasn't a friends name.
I can't see
Adelaide becoming really popular, especially in Australia- I think quite a few people will have trouble seperating it from the city. But
Matilda is on the way up I reckon.