I would skip the mirrorless option - there is no way an interchangeable lens camera will be as small as the Sony you linked. I have a Canon PowerShot S100, which I really like, it's about the same size as the Sony, and it fits perfectly in a pants pocket. I got the S100 for the high sensor size to camera size ratio (among the highest in the P&S category) with RAW capability - the new Sony has the highest ratio yet, shoots RAW, and I'm strongly considering picking one up for that reason.