I have always left feedback first for my buyers. eBay has really left us no other choice now anyway, so I look at this way- As a seller, I am rewarding them for their timely payment, and showing them professionalism as a quality seller who intends to follow through with quality service. It breaks the ice in the transaction and makes the buyer feel more confident in their purchase, and prompts them to leave you good feedback in return.
I still leave the feedback manually after shipping, and at the same time I send them a personal email (it's a copy and paste that I modify just slightly for each item) which advises them that their item has been shipped, when to expect it, tracking numbers if applicable, thank them very much for their business, and sign it including my website address. 15 minutes a day well spent. 😉
Cheers,
AXE