Standard - has a 20w motorhead attachment, this is the weakest of the series and a crevice tool.
Animal - wider motorised cleaner head attachment as the standard? In addition it has a mini motorhead for pets.
Fluffy - has all the above and one additional soft brush attachment specifically designed for bare / hardwood floors.
Total Clean - has all the above but a more powerful 35w direct-drive cleaner head - which replaces the standard 20w motorhead.
Absolute - has the mini pet tool as above, a more powerful 50w direct-drive than the Cleaner, and oddly, a very plain / simple attachment with silicon wipes for hardwood floors instead of soft brush attachment. In addition it has a Hepa filter at the motor exhaust - this also makes it a little heavier. All this will make the battery work a lot harder than the lower end versions.
Motorhead - released for the USA market only, so ignore it - Dyson only give warranty on UK versions, they won't even give warranty on any products for the European market - Dyson know by the serial number.