He takes every mark in his vicinity.
Possibly true - he's second in the comp for contested marks per game this season. Our own Turbo is 8th and only 0.27 of a mark behind.
However, Lobb doesn't even make the top 100 in the league for total marks per game. GWS's best forward is Patton at #58, ours is Kennedy at #36. The best full time forward is Hogan at #7, and Riewoldt (who has been the outlet on the wing) leads the competition. No primary ruckman is in the top 100.
Based on this season's stats Lobb has the averages of 1.7 contested marks, 1 total mark, and 0.5 goals per game over our own Lycett. He also has 0.9 less disposals, 1.4 less tackles, and 12.7 less hit-outs per game. He's 4 months and 15 games less experienced. The way the numbers stack up he's probably not worth any more than Lycett in salary, or in a trade.
In comparing with Naitanui he's up 0.9 contested marks, 2.1 total marks, 0.7 goals, but down 3.1 clearances, 27.9 hit-outs, 1.7 i50s, and 0.9 disposals. Lobb is more a marking forward, Naitanui is more a midfielder. You're probably not going to be able to replace Naitanui's impact with Lobb, but you'd likely replace Lycett. Question is can Lycett replace Naitanui (at least for a season)?