Well, this product is IMO the best version for the first 5 AC parts. Because, as far as I can overlook that, you get with this version even the most additional material for AC2 and AC: B. This is almost always reserved certain versions and editions. Since AC: R is with extensions probably correct money ...
For the first part, there is no extra material.
I do not know if it is already on the DVD, or if it will also be downloaded from the Internet. For AC2 the 2 extra sequences are simply there. For AC: B you have to Da Vinci's disappearance only unlock with one click in UPlay. Unlocking does not cost anything, you have to do only. For AC: R costs the DLC 'The Lost Archive "... probably. UPlay wants me though really sell much, but "The Lost Archive" I do not find ...
For AC3 I count at the moment 5 extensions and any costs.
The Copernicus Conspiracy (AC: B) is exclusively released for PlayStation and therefore not available for PC.
I do not care for alternative outfits and Multiplayer. Therefore, I do not know how much extra material is available here. For me, only the additional emissions are important.
Hope that helps in the purchase decision.