The main reason I prefer standard plate over tempered is if it breaks, most times it will simply crack and let your tank drain out through the crack. The silicone will usually hold it in place. If your lucky, that crack will be in the top half of the tank so you won't lose your fish. You won't have this chance with tempered as it will shatter into a thousand pieces dumping your fish out in one foul swoop just like the above pic. If the edges are not going to be protected, don't use tempered. As I understand it, tempered glass usually has slightly less clarity than float glass.