
Time is 880 build points divided by build power. Drain is mass and energy per second while it is building, so more build power finishes sooner and costs the same total, but pulls harder on the economy.
At 198 mass for 1500 health it is the cheapest T2 heavy tank and has the best health per mass of any T2 land unit, 7.6. It pays for that with the lowest damage of the four, 58.3 against 83.3, 116.7 and 120, so it holds ground rather than winning trades.