Personally I have never had any in my house, however practicing martial arts throughout the years, used quite a few of them. Definitely make sure the mounting look good (used bags that were too heavy for mounting and after few good kicks the mounting gave in and went out of the wall).
Second thing is - do you want it to be more of 'just' a punch bag, or more of 'realistic' experience with punches? personally, I find punch bags better for cardio/conditioning, but for more realistic angles (mainly uppercuts), either a standing dummy (Bob XL/ Bob type of thing) or something alongside of angled punch bags would be more useful whilst also being able to give you.
If I had a choice now to get one and put it somewhere, I'd probably go with angled punch bag as prime choice. If I knew that I have to constantly take it off / move it - I'd go for standing dummy.
And as mentioned - make sure to have decent mounting - I have no idea how much strength you have, but with time and correct form, you'll find yourself much harder hitting, so decent mounting will help!
Bit of ramble but hopefully it'll be of help