How long are these things supposed to last before the weird noises start? Do you believe they are necessary?
Never even come into contact with one. No idea if they are needed or just hype. I do know that if you spend a lot of time with your laptop actually on your lap it's as good as birth control though... yeah... the heat kills them... Laptops are designed from the manufacturer to have adequate cooling as-is with the rubber pads. If you feel you need a laptop cooler pad go for it.
I use the Cooler Master Cooling pad with built in fan. They do go bad eventually, and have to be replaced, but it does work very well.
True - when sitting on a flat surface. Before we got one for the family, I noticed that several of our friends had laptops that would shut off after 30 minutes or so due to overheating. Apparently many laptop cooling vents get clogged with lint (makes sense considering how they're normally used). In addition, some of the vents are blocked when a laptop sits on the lap. We got one of the cooling units but no one in the family ever turns it on. Even so, it serves it's purpose for providing a flat surface so the ports are not blocked as my kids/wife use it on their lap or couch or rug or .... Ours is a Rosewill. It's mostly metal and reasonably well made. For the small cost, it seems worthwhile. All the best, R