The base comparison is lopsided: the R12 V2 gives you 12 Nm for $399 and scores higher on our rubric, while the T818 asks nearly four times as much for 10 Nm. As pure wheelbases there is no contest - the MOZA is the mid-tier value benchmark, crisp and detailed, for the price most brands charge for a wheel and base together.
What the T818 sells is the Thrustmaster ecosystem. It is the brand's first credible direct drive base, and the SF1000 rim catalogue is the real reason to buy it - F1-style wheels and the Thrustmaster mount, ready to go. If you already own Thrustmaster gear or you want that specific ecosystem, that is the pull. On merit and value, though, the R12 V2 is the far better base for almost everyone else.