Hi James and welcome to the forum.
To answer your second question first, all of our suppliers are fully verified and approved by us. They undergo quite a strict application process that see many fail on minor issues. This is how we maintain the highest level of safety for our members.
In regards to finding good suppliers, well everyone may be looking for something different from a supplier. So that's a question you really need to answer yourself, based on what it is you in particular are looking for from a supplier.