I think there's got to be more than mere preference, or tossing a coin.
Can you try the slips out with your boat?
What was does the stern pull with prop walk?
Where do the strong storm winds come from and is it better to be held off the pier when it blows?
When you go into the slip do you "flare out"? If so is one slip better for it?
Which of your lifelines has the better gate?
Where are the power and water plugs?
I think there's lots to think about!
If you are a newby and you don't mind telling people that, then you may be able to have a chat to some of the other skippers... The marina staff won't know...
If docking and leaviving is easy, simple and easy and simple you will be able to do it by yourself and so when you have an hour free from work etc you can go out for an hour, or just a few minutes. If your dock is a pain you may never want to go out!
I love just jumping in and going