Which wireless alarm system is best?

I am looking to install a wireless security system in my house. It is a ranch home built in the late 50's. It is about 3500 sq/ft upstairs and 2000 sq/ft downstairs.

~ 45% of the windows are casement and ~ 50% are picture windows, the remainder I'll call "other".

I'm curious as to who makes the best products/systems that I can add to if needed. Should I put contact type alarms on the windows or the type that alarm when the window is shattered?

I would like to also put some alarms in my downstairs as there are 2 doors and more windows.

Any suggestions on manufacturers and types/styles of alarms would be greatly appreciated.

Thanks in advance