I know TheO really well, firstly it's a great product. They are basically heated velcro rollers however my issue too is the price. I think the amount of £200 is a lot for a styling product and you also have to spend out £18 if you need additional sizes and packs of rollers. The price point has stopped Theo igniting into a real 'must have' item.
I would actually suggest you save yourself the money initially and buy these:-
I will give you another tip, if you like the really big velcro roller effect, buy the above rollers and begin winding them into your hair. With every third to fourth roller applied, go back four rollers (applied) and unwind the hair and replace quickly around a large velcro roller. So you are basically winding the hair on the hot rollers, heating it up and then when the curl begins to form replacing the hair (whilst still hot) with a large velcro roller. This will then create more of a blow-dried effect if you like that look.
However, these rollers I have given the link to are very good if you just want quick bigger curls.