How does it feel when you get all of your teeth pulled for an immediate denture?

PAINFUL. Swollen, mouth bleeding. A mess for a few days.
Uncomfortable. Everybody's pain threshold is different, after extractions, but remember you are in the healing phase now and things will get better rapidly... Your dentist will make adjustments to help the process.
It takes patience... During the tooth extractions, it does not feel like much at all, because local anesthetic is used to block sensory perception. It usually takes some time after that to become accustomed to the feel of dentures in the mouth. Discomfort from pressure between the denture base and the fresh extraction sockets can be controlled with topical anesthetics and adjustment of the denture base by your dentist.
Sore, strange, . Pain from tooth extractions, pain varies on difficulty of extractions and expertise of doctor. Weird due to a foreign object present. Loss of significant ammount of taste. Foreign object (denture) stimulates more saliva production, plan on alot of drooling. Remember dentures should be a last resort option, not a cheap easy fix. Also the best denture is 40% as efficient as your original.