Right now I'd say that Super mines still needs to be buffed greatly. The nerfed Perma-spike has the same attack speed, I think, and is actually fairly well balanced in my opinion (the 0-2-5 can only absorb ~40000 RBE at this point, equivalent to 10 or 11 1-2-0 spike factories, which have approximately the same cost). Super mines should probably cost around $50000 if its attack speed is not increased. If the explosions do not affect DDTs, that would be a bug, not something intended.