These compression bags work really well. They compress your packing to create additional space in luggage, keep everything neat, tidy and accessible and the clothes come out less wrinkled than with conventional packing. Sometimes they can be a little hard to zip up at first but once you develop the technique you'll never go back. I wouldn't travel without them now.
These are great value and work well, only issue is the compression zip which can sometimes get stuck on the material when trying to do up, you just need to be careful when using this and use your forefinger to guide the zip.