There are three major ones in different buildings. And if you only do two, I would recommend first, the one in the Farmiloe Building... but mainly for the building itself.
Industri UK, where you can take an online walkthrough tour of this wonderful place (it hires such buildings out for big events).
This is also where you'll find lots if up-and-coming rather than established designers showing their wares. Check out Irish designer, Donna Bates, aka I Do Cartwheels – her milkshed inspired lighting is brilliantly unusual. While recent graduate, Freyja Sewell's HUSH Chair (pictured below) is something we could all surely do with after long working week, or a big night out. For a full list of exhibitors, click here (once there, click on their logos and you'll get images and links to their individual sites. Be warned, you will lose several hours...).