There are four houses you can join in Hogwarts, and while each house is distinct, it's important to note that
much of what you experience will be the same no matter which house you choose. The most important differences you will encounter involve the following:
- The House Colours incorporated into some of your gear will reflect your chosen house
- Exclusive access to your Common Room location (and a Floo Flame fast travel point not accessible to other houses)
- Extra socializing and introductions with other 5th year students in your house
- Certain extra dialogue that may reference your house
There does not appear to be any inherent bonuses, perks, or exclusive companions that are locked to one house. In fact, regardless of your house, you'll be able to socialize, undertake quests, and even group up with 5th year students from each of the houses - and some will have their own questlines that don't rely on you being in the same house as them.