Yes, it's worth 20$, either if it's the 3 CD-box, or the 10 CD + 2 DVD -box.
That's my opinion at least. I have both, and I paid a lot more for them...
I think that because it's PAL not NTSC.
I bought this as an NTSC, factory sealed set from ebay over a year ago and it was 3x this price. Frustrating because the PAL versions were a whole lot less even then.
I'd still read the fine print, however. There's another set offered on ebay that does NOT include the book or any other inserts, just the CD's and DVDs. Caution couldn't hurt.