I have used a 45 mm Martelli for about 7 years. I just recently bought a 60 mm for cutting thru 8 layers of fabric to make a One Block Wonder quilt. I had problems with my thumbs / wrists and tendonitis. Pushing down to cut thru many layers of fabric with a stick handle type of rotary cutter was painful for me. That's why I switched to Martelli's style of cutter. I didn't feel like it was difficult or took a long time to get used to using it. Martelli does have videos that show how to properly use their cutters, as well as how to take them apart to clean them and replace the blade. Watch those videos as they are very informative and helpful, especially for cleaning your cutter. They have improved the cutters over the years. My spring broke within the first year of use. I brought it back to the shop I'd bought it from and they contacted the company for me. I received a FREE new spring along with good instructions of how to replace it. Martelli stands behind their products. I have not used the QS rotary cutter.