I hope you'll forgive me for skipping T1 AA (Not much to discuss) and lumping the mainline and amphib tanks together. Still experimenting with this format so let me know whether you'd prefer more narrow or wide discussions.
Here you can share your thoughts on the following units:
UEF: Pillar and Riptide
Cybran: Rhino and Wagner
Aeon: Obsidian and Blaze
Seraphim: Ilshie and [I'm not dignifying the sera T2 amphib tank by looking up its name]