I use 3/4c dextrose on pretty much all my beers. Works well in a crowded area.
I like munton's carb tabs because they make it easy to adjust your carbonation level and also allows you to use larger-format bottles. The cooper's are just one tab per 12oz bottle...so what happens when you have one of those 16oz german-style bottles? With munton's, you add 3 for low carb level in a 12oz bottle, 4 for regular, and 5 for high. For larger format bottles, just do the math.
I wouldn't use carb tabs unless you really need to though. They're much more expensive than just using dextrose. I use them when bottles don't carbonate and I have to uncap-recap them...or when I have a batch that's smaller than 5 gals...makes it easy.