Let me start by saying my experience is the price of basic insect screens with cheap plastic frames and parts have mind boggling prices--and they are total junk fitted using a bead of silicon that covers up and ruins the high quality look of your beautiful window frames. But then if you look at the price of security screens they are just insanely expensive. Given a choice between the two, I'd go for the latter because even though they are overpriced at least you end up with a high quality product with a durable frame built to last available in a rich powder coated color range that looks great and adds a layer of security to your property. I listed web sites of two manufacturers of security screens earlier. Recommend looking at each, haggle a lot. At the end of the day, I don't think the difference in security between the two is significant for a thief with the right tools. They would both stop some types of thieves, but not others. And some prefer breaking in through the roof anyway.

My house doesn't have a loft hence no door so guess they would need to kick through the ceiling if they broke into the roof.

Actually most homes have an access square that can be lifted out in ceiling (most often in bathroom) as under roof access is required for wires and checking for leaks/condition (and in many cases sewer vent ends in this space and access would be required to clean it).  

19 hours ago, stament said:

My house doesn't have a loft hence no door so guess they would need to kick through the ceiling if they broke into the roof.

 

Are you thinking a burglar wouldn't kick through the ceiling?