I discovered that it doesn't just take batteries, it also has a power cord, so I could have just plugged it in and given it a whirl straight away!
It's much smaller than I imagined it would be, which is great because it will be easy to store amongst the mounting piles of fabric and sewing supplies. I had three different types of bobbins on hand, so I decided to try them all to determine which one was the best to use.
Please note that I am not a bobbin afficionado, so I will just describe them by type and hopefully it will all make sense.
First up was the plastic mushroom shape bobbin (it has a slightly curvy top and bottom). It all started ok, but then the cotton started to twirl itself around the post because of the curvy bottom on the bobbin. It ended up being a dismal failure.
Next up was the plastic bobbin with the flat top and bottom. There were no problems with this one. The sidewinder filled the bobbin and then stopped automatically when it was full.
If you do a lot of sewing and really hate unthreading the machine each time the bobbin runs out, then this is the perfect little sewing gadget for you. It's certainly not a necessity but it's just one of those things that is nice to have and at $30, it's not really going to break the bank.
The only drawback that I can envisage is that if you don't have a large supply of cotton on hand, and you need to match the cotton that is currently being used on the sewing machine, then you will still need to unthread the machine to fill a bobbin.