If the goal is draw-go, Thrasios is the much better partner. Having an EOT mana sink plus access to ramp is huge. I play a Smasher/Thrasios deck, and it plays like BUGr control. I haven't found mana consistency to be an issue so long as green makes up a consistent part of the deck for ramp.
Consistency in 3c or ramp in 4c?
Hightower | Vial/Thrasios | Mogis | Grenzo | Endrek |
Tatyova|Sisay|Zurgo|Breya|Chisei|Marchesa|Olivia|KaradorPauper | Pauper |
Legacy|4fun|4fun|Modern|Frontier|Standardstuff