Gotcha. Used to do low voltage installations (home automation, security, etc..) and so I've decent wireless systems, and not-so-decent ones that were just a constant pain. I'm sure you will or have already done so, but ask around for others that may have a similar wireless setup as you're looking at and see what they think and if they've had any maintenance issues.
Sometimes running wires is just out of the question, but when able to it's just more reliable. People are surprised where we can get a wire to.
The cellular connections are just plain cool. Got out of the industry as those were really catching on so only done a few (and those were mostly cell as a backup and not the primary communication means) but haven't had any issues with the ones I've seen. I'm really NOT a fan of internet based monitoring, unless there's a landline or cell backup. We all know how reliable our internet service is......
The other little detail that is nice is to use recessed window contacts IN the actual window frame, instead of being surface mounted. Hides the contact and you don't worry about the contact falling off if the adhesive fails. Probably applies a little more for new construction, but we've put some of those in on existing construction/retros.