I have only used plastic. Is there an advantage to using metal ones?

The rule of thumb I've been told is metal for metal bobbin cases and plastic for plastic ones.

I use the same type that came with each of my machines. I have been told if you use a metal bobbin in a machine that came with plastic...you will wear everything out faster as the machine was never meant for metal bobbins and visa-versa.

I sew with a vintage machine and I prefer metal over plastic. Over time the plastic wears and distorts.

Plastic can get burrs on them too, which can make your stitches mess up. I soooo prefer the metal over the plastic, but my new machines can't use them :D:D:D

I believe you can fill the metal bobbins with more thread than the plastic ones. Have you noticed this or am I confused?

Think you might be right .... seems that way to me anyway.

I use either.

Please use whichever type of bobbin that originally came with your machine....if it is plastic...stick with it...even if the metal fits.
You can cause damage to your bobbin case with the wrong kind.

Yes!! Vintage machines and machines with metal cases were engineered and manufactured to take metal bobbins. Newer machines with plastic bobbin cases are engineered and spec'd for plastic. Just because it fits, doesn't mean you should use it.

I guess I just thought plastic meant cheap and metal meant quality, so I thought I was missing something. Guess not. Thanks :)

I much, much prefer metal!

I agree with Candace and besides my machine dealer definitely told me NOT to use metal bobbins with new machines and would become a very expensive fix. The new machines are definitely not geared for metal bobbins but he old ones are.

i just use the type that comes with my machine. i have had both.

I remember being told at the LQS that metal bobbins are a good investment and are better for your machine. Then I bought quite a few of them at one time and it turned out they worked horribly in both of my Janome machines. Now I use Janome brand plastic bobbins only and I have zero problems. In fact, I went through my entire sewing room and threw out anything that didn't come straight from the dealer. I didn't need the headache.

I use the pre wound bobbins and ocassionally use my metal bobbins if I have to wind a color.

I have Janome machines and only use the plastic bobbins that came with those machines. Good way to mess up your machines is using the wrong kind of bobbin.