In short, it is not perfect but it ain't bad. I rate it 8 of 10. I am a tough grader; my RockChucker only gets a 9 of 10. https://fsreloading.com/ergo_prime-90250.html The weight and ergonomics are excellent, some of Lee's equipment has a cheap plastic feel, this unit does not. Very smooth and effortless action. First ding on the design: I thought the square pans were going to be able to take a full flat primer tray and inver them with the primer laying flat, nope they are a triangular section raises to guide the primer into the feed channel. Most of them fit but you still have to play with 2-3 primers. Still much better than the old round design. Second ding: is for reliable operation of the two stage primer feed operation you have the hold the tool only 10-20° up from horizontal. What that means in if you have a case in the tool and you are pointing at a wall a line eminating from the case would be tilted up 10-20° from horizontal. If you do not do this then the primers do not feed consistantly in to the two stage operation. What was happening to me was that 2 primers would bet double stacked on the first stage ram and lift the plastic cover off the tray, possible spilling primers all over. I did not spill any and figured out how to get them to feed consistantly. Once you get the hang of the angle, it does prime fast with little to no fatigue. Again a very smooth action.