I've had a zip pressure cooker for 20 years and occasionally used to forget to check the food. I would come back and the food was burned or overcooked. The timer doesn't start until it comes to pressure, so my food has been spot on every time so far. I decided to get the larger size this time, as I like to cook a lot of soups and legumes, which require a bigger pot. The only negative is just that I can't tip it up whilst still on the stove, because it hits the extractor fan above.
The timer is perfect for me. I'm a busy person and often forget about my pots on the stove.