Those stoves with hexamine are standard issue in the british military, I used them for years with no complaints. One tablet will boil a gallon of water easily.
The first time I used an alcohol stove I thought it was a joke, it used so much fuel.
In fact there is a place for both. The difference was the Trianga works well in the wind. A hexamine sometimes doesn't work at all in it. A bit of foil and some tent pegs will make your hexamine stove good for most uses. They are also so cheap you can buy a few and throw them in the bottom of your bag or the car and forget them. And it's the only fuel you can fly with.
But if you are planning on cooking on the side of a mountain the Trianga will work better.
The Sock