Yes, there are big differences. The best ones are very supple and won't transmit vibration to the camera if your hand shakes during exposure. I have had this happen with a cheap one that had a stiff plastic coating on the outside. The one i use now is a Prontor cable release, made by the shutter manufacturer. It is so supple that i can tie it in a knot and it still pushes smoothly! and it doesn't shake my camera if i move during exposure. I don't know if they're still made, or what they cost. I got mine when I was 15 at a photo flea market. The man who sold it to me had it in a Vivitar zip-lock filter sleeve, and at the time I assumed it was a cheap Vivitar release. I got it for $5. Later, when i was in college, I discovered that it was a rather costly one that was about $100 new!
I wouldn't buy a cable release mail order....go to a local store and look at....feel..all of them and buy one that's soft and supple, not stiff. A good one will last many, many years so its worth the investment. I still have that Prontor one 17 years after buying it for $5!