i use my 28 mm cutter alot- it is great for curves, small shapes- less slip ups - easier to get into (or around) the smaller shapes/curves that the 45 is simply too large for- but i had it for 3 or 4 years before i used it at all- i guess it depends on how much curved piecing you do??? i've found that lots of my tools spend long periods of time in a drawer- then all of a sudden i need them- and wonder why it took me so long- but then when i've moved on to other things they go back in the drawer- i have an 18 too- i use that one more than the 28---i do alot of applique- and it is great for small pieces.