I decided to use "Add This" share buttons and have added both the side buttons, as well as the floating mobile share and follow buttons.
14 OCTOBER UPDATE
Decided to switch from Add This to Sumo Me and think it was definitely the right decision - Sumo Me offers so many more applications with their free version (heat maps, google analytics simplified, customised share buttons, scroll bar, welcome map).
Also installed the Hello bar that should pop up before users leave the site. The interesting thing is that it allow s for A/B testing even with the free version so let's see how that goes. While I hate pop-ups, especially those that pop-up right as you click on the site, I actually think a pop-up before a user leaves, with a final plea for a donation may work.
Over to you, what do you think?