We have one, and in the 2+ yrs we've had it, it has only stuffed up once, and that was from Dad getting a bit too quick at loading it.
If you can work out where the CD is actually stuck, try getting a flat, dull object (like a small screwdriver) and prying it out. I know that sounds downright stupid, but it worked for us and its left no issues afterwards, just use it to help get the CD moving again and it should be fine.
Failing that, any half decent car radio installer should be able to get it out for you for a minimal fee (if theyre any good, its a 30 second job). Ive seen a guy do it here once and it took him all of 10 seconds - and it was the same problem, disc was stuck.
AUGZMK, do you have any idea if the boot stacker is compatible with the 6 disc in dash unit? I highly doubt it is, but it might be a good way to double your CD capacity