I use Fibrax sintered and they seem ok. I have used the cheap Imperial pads before (same as the Superstar ones I think) and they were good until the pad came off the backing.
Fine if your jsut riding round the local woods, not worth the risk if your going to Canada. Saying that, Ive jsut ordered some A2Z ones for my trip to france but Ive only ever heard praise for them.
Fitted superstar ones for our annual lets push up Snowdon jaunt and they didn’t like coming back down at all!!! In fact one pad didn’t make it to the bottom, to be fair tho i fitted the cheapest ones, not sintered. So its a case of you get what you pay for i guess.