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.
A horse may be one of four different rarity levels: Special, Rare, Elite, and Mythic. In general, Mythic horses have better stats and skills than Elite horses, which are better than Rare horses, which are better than Special horses. All horse breeds can reach a higher rarity level (and tier) through breeding.