Neighbour's cat has taken a liking towards us?

So, in September last year, we had new neighbours move in with their lovely black cat. At first she was a bit timid but still let us stroke her and came over if we called her. The owners had no problem with us doing so. A few months later, we stroke her for a few minutes and she hisses at us (what is that about)? She is terrified of my dad but loves me and my mum. Since about last week she has been a really loving cat. We see her almost everyday (as she loves chilling in our garden and playing) and from about last week she came up to me and my mum, we stroked her for a bit while sitting on the garden chairs and she jumped on my mums lap.   The following day, she does it again, my mum goes inside and she decides to lounge on my lap. We noticed that this cat is outside most of the day, except in the evenings. Whenever we go out into the garden, she'll be jumping over the fence and into our garden in no time. Personally, I don't think she's getting enough attention at home (they've just had a second baby). So my question is, does she like us?

P.S. - Saw her in the garden today and when she saw me she ran up to our house door, I stroked her for a bit and she is still sitting by the door.

We also have NEVER let her in the house (although she jumped in once and started hissing at us) and we haven't fed her anything.

Just be friendly to her. She probably is a little overlooked as her human parents must be very tired etc.

Her hissing is her way of letting you know she belongs to someone else, but your friendship is appreciated.

She came to me today when I was out in the garden. I stroked her for a bit then out of no where she grabbed hold of my arm with her two front paws (claws out) and hissed at me. Needless to say, even through my hoodie sleeves, I still have quite a long scratch. What could of caused this behavior?