3008 is a beautiful and safe SUV fit for the purpose that you are looking for. If you going for brand new then you need not to really worry about maintenance cost as with every new model it comes with free service and maintenance contract if I am not wrong. Even if i am wrong, new Peugeot is very good for 3-5 years easily without throwing hefty maint bills so you are again covered.
Yes if you compare that size of vehicle with 208 or 308 then yes it cost slightly more maintenance, but try comparing with other SUV to be fair in same league as VW, Nissan, Toyota etc.