The mounts is Praxon Firaxa and drops exclusively from Warlord Kephess on Nightmare Mode, however is can drop from both 8man and 16man (two of my guildmates got it from clears last few weeks. However it has only dropped twice since EC Nightmare came into the game (we cleared it since first week) so it's not a 100% drop rate.
The tanks look cooler. Actually, the Bloodline looks better (imo) than the Firaxa. It's a shame when the HM speeders look cooler (subjective I know, I know) than the NM speeders.