I'm still trying to decide what I'm going to top my Vamo with also. I was looking at the Smoktech R-tank besides the AGA's. The O.D. is fairly similar. It looks really easy to rebuild too. After seeing the cracks in that Tiamat tank, if I do go with an AGA, I think I'll go with the Hydra and skip the extra tank cost...
Yeah, that tank cracking is weird. It's pretty thick plastic. It has to be the juice. I've had 3 AGA-Ts going for over a month, all filled with various DIY stuff, and no cracks.