Hi Mairead,

There's no simple answer to such a question, and it's made more difficult by a lack of model year information. We'd avoid any diesel engine unless you plan on driving over 30,000km a year - and most of that at motorway speeds - as the use a particulate filter that can clog up with slow-speed use. The 3008 is a much larger car inside than the Focus, but the Focus is more efficient and a little better to drive. 

Really, you'll need to drive both cars for yourself and weigh up the pros and cons mentioned above against your own circumstances to answer the question.