I played against Dr Evil on Jinteki some time ago and he asked me why i like and play Hayley (namely my list).
I told him that I love playing two cards simultaneously IRL, it feels fresh in a CCG.
However, the more I see and play @spags list, the main difference is this.
Technical Hayley plays more like an Andromeda "The Deck" list of old. You set up your rig and an economy engine, both better than the corp most of the times. You have to take decisions whether to run or hold and your main goal is to go for the RnD lock. You still play a lot of cards and do some #shaperbullshit but not as many.
@spags Hayley reminds me more of a PPVP Kate build. It is more reactive and oppressive. You will run and find the answers mid run, use stimhack for surprise pressure and stuff and do not rely so much on credits that your opponent can actually count and take into account in his turn.
I still like playing my list more since I never liked PPVP Kate (ask @groober for crushing me twice in the Greek nationals just because I did not want to play PPVP Kate, clearly the better deck at that time). However, @spags list offers more creativity and reaction, some may feel that it offers a more interactive game, and yes it is really good..
Just my $0,05.