The Region 1 DVD set, from Rhino Home Video, includes the first 24 episodes spread over 3½ discs. The fourth disc contains three episodes, a mistake reel, a documentary on Botcon 2002 and interviews with 2 voice actors and 1 script writer. All episodes have been mastered in Dolby 5.1 Audio. The second set, contains the remaining 25 episodes and more features also spread out over 4 discs.
The NTSC VHS set, also from Rhino Home Video, contains just the first 24 episodes spread across 4 tapes. The remaining 25 episodes should be on the second set, although Amazon's details on the second set are sketchy at best, making it appear as though it's from a different distributor or something -- best bet to stick with the DVDs if you're able.
The Region 2 DVD set, from Metrodome Distribution, Ltd., also includes the first 24 episodes, presumably on 3½ discs as well. According to Amazon.co.uk, special features include a mistake reel, 2 episode scripts, a quiz, character profiles and more. The second set of the second season for Region 2, appears similar to the Region 1 set up, although with different bonus extras (better than the U.S. ones by the looks of things, IMHO--somebody give my a multi-region DVD player please).
*Season 2 episodes on PAL VHS seem to be scattered if they are there at all. This link will direct you do to Transformers VHS search results on Amazon.co.uk.