If you can adjust the sensitivity then maybe, but you'll be vulnerable to cat burglars.

I bought one after being burgled two years ago. It was mainly as a deterrent.
I was burgled again three months ago, broke in through a window I did not have a sensor on (it does now!). They tripped the PIR sensor and the device called me alerting me whilst sounding the alarm. The alarm sacred the thieves off as my neighbours, who were alerted by the alarm, saw them running away. My system now has 10 sensors on it rather than the original 4 - and I was able to fit them myself.
So it DOES work. I lost nothing in that burglary! Im not sure what the previous comments are referring to but this is an easy to install alarm that can be scaled up. The sensors are all tamper proof and I can state they this function works week as I accidentally set it off the other week but not fixing the sensors on securely enough after getting some work done to my windows.
In addition to this, one of my original PIR sensors caused two false alarms. I contacted Yale who sent me a replacement out free of charge - without requiring the faulty unit be returned first.
This might not be a fully monitored solution that send Group 4 round to check on your house after an activation but the difference in price between the two is vast. This is most certainly a decent system for what it does.

has anyone got a personal review of these alarms ?

I like to know this as well, anyone who got this and how effective they are?

I've had one for the last 9 years rarely get false positives, really good alarm system. Easy to install. Only now is it beginning to play up.... I'm going to replace it with this model.

I bought one 6 months ago. I also bought the option remote key fobs too. System works really well and very easy to fit.

I have on too. Easy to install. Took about 2hour to fit everything. I would get extra fobs as the wireless keypad is abit naff. I use it for emergency in a draw, hidden away.

My work moaned at me and said it would be crap, but so far after over a 1 year I have had to change the batteries in 1 sensor. The telephone dial out works well. For the price you won't get better.
The only thing I would say if you are going all out they now do one with fire sensors and cctv built in...
So you get pictures sent to you if the alarm goes off...

Does anyone know if it will work with cats at home ? I have 3 cats and wouldn't want to get false alarms.

I've read in many places that these are very easy to hack..is that right? I'm currently refurbing a property so looking for a decent alarm system whether that be wireless or wired.

They can easily be effected by interference either intentionally or unintentionally so much so that the manufacturer recommends in the instructions to turn the 'jamming' detection function off. Also as these are 1 way wireless rather than 2 way this makes the above even more important when deciding what to choose.

If you are refurbing a place then run wires, no brainer really.