I do have this brand for my 4 dwarf Robvoroski hamsters. However I have bought quite a few different bits 2 attatch it 2 such as habitrail and it gives my hamsters not only freedom but also plenty of places to excercise and sleep. They love it, if any ever escape they go straight back!
One thing worth mentioning though, these cages are most certainly not suitable for larger species of hamster such as syrian as the cage does not allow much room for running around (and believe you me, even after a couple of hours in a ball they still have energy to spare!) but I have found the habitrail good for the larger hamsters. I believe Pets at Home have a varied range.
Cages with bars are very good as hamsters like to climb, it gives them more to explore and do in their home!