I have been using both k30 and k5iis,always carry them when shooting,so dun need to swap lens mah. To me,there are differences: In raw file process ,I can get more detail, sharpness and dynamic range from k5iis.It also has more control and setting to play with.Using with battery grip, I am able to shoot more than 1k photo.K30 is good enough , If u are not pixel peeping.If your budget can stretch ,k5iis is a good choice,otherwise k30 .U will not go wrong with either.