I'm a UL certified security contractor. That being said, let me explain to you what I explain to all my customers;
A security system is a deterrent and something to give you time to assess an impending threat. It is not a way to keep people out, only slow them down. $99 ADT installs are laughable and completely inadequate. The Simpli Safe systems are ok for what they are, but also inadequate. The way I look at a system is simple; you need a dual mode motion (passive IR and microwave) in every room, including your garage, that covers every inch of a room from floor to 6' high, door contacts on all exterior doors, and some sort of interface between yourself and the system in case you are not home, i.e. an app for your phone that alerts you and will also allow you to arm and disarm from afar. Your neighbors may hate you but a couple of 150dB alarm horns mounted on the eaves of the house get everyone's attention should something happen. Burglars/Home Invaders don't like spectators.
Monitoring a burglar alarm is fine and dandy, but the police respond slowly on purpose to alarm calls so the perps will be gone before they arrive. I have been called out on an alarm call and arrived before the police and I was 20 minutes away. They don't care about your stuff as much as getting home in one piece.
Barricading a door is ok, but I could climb through a window a lot easier than busting down or through that door. I'm not saying don't barricade your basement door, just that a burglar usually looks for the path of least resistance.
Maybe there are no windows, so you think you're good because you barred the door? I can take a sawzall and enter right next to it in about 1 minute without setting off a door sensor, but if you have a motion you got me. Odds are Leroy Criminal III will give up and find an easier access point if he finds the door to be a problem for him.
I can go in depth into why I don't think glass break sensors are useful, and why you need dual mode motions as opposed to passive IR only, and will be glad to answer any questions or elaborate on this.
The question is, do you want a perimeter intrusion detection system or a security system?