mine was a Photix one, bought from Hong Kong for $65AUD shipped!
Its got to be
THE most useful thing to have for DSLR astro imaging.. prior to that I had been using a manual shutter release cable, timing my exposures with my wrist watch... Not a relaxing task.. Now, get the target framed, set the start delay, interval, exposure duration and exposure count settings, press start and walk away..
Fantastic bit of gear! And why would you pay nearly $300 for the Canon branded unit?