left and right hand

Do those make a noticeable difference?

for sure .............. make it easier and give a straighter stitch , when I used to do it without I could get it more or less spot on but if it was a long straight line I could see a slight imperfection even though the customer couldn't but with a guide they are perfect

I use the same ones.The thing is you'll find all sorts of uses for them once you have them, the 1/4 inch ones I'll use if I need to sew two parallel lines on a door card or seat panel(3/16 for porsche), I make some tool bags and the 3/16 is useful for a stitch even to the outside edge of the panel.

I have the same ones. I was hesitant at first to use them cause I thought I was cheating but no way! After using them once it makes life so much less stressful and the spring loaded part actually pushes the material down some so you have less of a chance of wrinkles or puckers around corners. Well worth the $20.

Awesome guys! Thanks so much for the tips.