Personally, I think they are unsightly, makes me feel like I'm in a cage and worry about there only being one exit in case of fire etc.
OK, on some houses, especially if on their own outside an estate may need them depend on the "locallity".
I, however, would be interested on views from being inside a modern estate with the usual security etc. Seems though, that all the Thais are totally convinced you need them.
Are the metal bars really necessary? Also, you can't clean the windows properly with them on. I would like to avoid putting them in but if it proves to be universally considered prudent then will do it.

I kind of like the idea of a camera or two, wifi alarm and a couple of motion detectors around the house which slam on a load of lights in the garden if is disturbed etc.
What's the genernal consensus folks? How much risk are you actually at in reality without the bars?
What are your recommended security solutions in this estate environment?
All comments welcome as I'm trying to decide whether to have the things put in or not.
Added a poll too.

Edit - Typos and slight alteration to a poll option to give clarity