It will feel like some one is pushing on your teeth. The brackets stick out a bit from your teeth making it feel like you have a full mouth of metal, big lips and your bracket may rub against your lips feeling again like a metal file.
While some breeds may be more suitable than others for a beginner rider, there are always exceptions to the rule. Quarter Horses often make great beginner horses because of their even temperament, but some can be quite hot or energetic for a beginner.
The horse that would be best for all 3 of those is the horse that is well conformed, athletic, and willing to please, regardless of breed. Generally speaking, the horses that excel at barrels and poles are stock breed horses; quarter horses, paints, appaloosas, etc.