The first Region 1 DVD set, from Rhino Home Video, includes the first 16 episodes spread over 3 discs. Also on the third disc you will find historic trailers, a documentary on 2003 Transformers convention and Transformers Public Service Announcements. All episodes have been mastered in Dolby 5.1 Audio. The second set, contains the remaining 14 episodes of the 3rd season and the only 3 episodes that comprised fourth season as well as more features also spread out over 3 discs.
* Amazon doesn't seem to carry either the 3rd or 4th seasons on VHS. The above links will give you the VHS search results for Transformers on Amazon.com and Amazon.ca respectively.
The Region 2 DVD set, from Metrodome Distribution, Ltd., will be out on July 19 of this year. So far their are no details as to exactly how many or which episodes it will include. Also unknown is whether it will include the 4th season at all.
*Season 3 episodes on PAL VHS seem to be scattered if they are there at all. This link will direct you to Transformers VHS search results on Amazon.co.uk.