Depends on what you want, monitored or not.
I have a monitored system that is currently with CPI and I am so happy with their service. Prior to CPI I had ADT and I do not have very much good to say about ADT.
My first gripe, was the sales person bold faced lied to me regarding questions for what I needed. ADT has a six moth money back guarantee if the customer is not satisfied, and I had to bend over backwards to get ADT to honor it. My complaint to ADT to document my issues is about 5 pages long in 12 pt font but I will briefly explain my complaints:
1. I wanted more than door/window intrusion and I was sold motion sensors. I have pets (cats) and my concern was my pets setting off the motion senors. I was told no, they are pet immune. Turned out not true at all, when I left and when my cats came downstairs, with my motion sensors on, I got notified there was am activation.
2. When my pets set off the "supposedly pet immune" motion sensors enough, I called ADT and the advise I was given was to cover up the motion sensors when I was away. Made lots of sense
to do with monitors that I paid for and for a service I was paying for
3. I called my sales person for options, he called back some time later saying that he talked with his manager and they could give me a whopping 10% to buy glass break sensors to replace the motion sensors. Again I clearly express my concerns with motion sensors when I bought the service. Shortly after I returned his call and told mim that was an unacceptable option and I wanted to invoke my six month satisfaction guarantee, and this was after he reminded me I could invoke it. My sales person then told me that his manager would need to speak to me and he would be able to do so.
4. Weeks go by and no call from his manager. I call several times with no reply; eventually I do get a message from my sales person that he was at a "manager" meeting and would call. More weeks go by and nothing. I call my sales person many more times with no response; again I finally get a message from my sales person that he and his manager has tried to call me multiple times with no reply. Not possible, I do not turn off my phone, so I had no miss calls or messages. Plus he knew my cell phone number because he called it to make the sale and it is on my contract.
To shorten my comments:
5. Finally heard from the manager months later, he had no clue what was going on, or what I formally wrote in my letter that I mailed certified or problem. After discrediting his arguments, he swore he would authorize my money guarantee and refund it to me. Months go by and nothing!
6. After calling ADT directly and being passed off to the local office/franchise (no answer or return call), I finally found a number to customer satisfaction (I believe that was who I called) and I got some help.
7. When a tech came to pick up the equipment, they tried to take my glass break sensors, was not provided by ADT but the sales person tried to sell me, but were instead purchased from CPI.
Aside from my complaints above, the remote system (I can not remember what it was called) is antiquated! It has to be hard wired to the modem!
So from my experiences with ADT, I would not recommend ADT. CPI is so much better for what it offers, technically advanced and costs less and I have had CPI for a year now and I am happy.
My system is monitored. Regarding the cost, that will be how many doors and windows you want connected along with glass break, fire/smoke monitoring, remote system, etc. So that would be something per individual and what I pay for most of the bells and whistles will not be an accurate measuring stick for you. Call and talk to services and see what is best for you. I have expressed my experiences with ADT and CPI.