We had a really nice stay in Lisboa in Sheila's appartment, thanks !
Positive points : the place is big and is well equiped (also for children and babies), Sheila is welcoming and reactive, metro and bus stations nearby.
Negative point, there is one : the beds are not comfortable at all, you can feel the metallic springs when you lie down.
Also, a note for those not in a great physical shape, the access from buses and metro can be exhausting as the flat is at the 2nd floor, on top of a hill.