Welcome! I would definetely recommend getting the 15mm swirl killer first. If you want to add a second down the road, you would then want to get the SK mini. I have both and I absolutely love, and highly recommend. As BrianT said already, other polishers will vibrate much more than the SK, causing considerably more arm fatigue. The SK is a night and day difference, making for a much more pleasureable experience when polishing!!