Doom Divers can come in very handy, especially to target long range and force your enemy's hand (onto the tabletop with his tape measure to move his army into combat !)
Divers are probably worth the points (80), which is 10 more points than a rock lobber, because they are slightly (D3 inches) more accurate, so rolling a 2 on the artillery dice will usually still result in a partial hit.
However, there is a BIG problem with divers in games below 2000 pts... They use up your rare unit choice which you need for a Giant !
