Sled Question

A quick question concerning sled use. I have access to both a 5 man lev sled and a 5 man traditional sled. In the past when I coached TE and JV O-Line, the O-Line coach used the traditional sled almost exclusively. In my opinion it is a great hoot and holler piece of equipment, but now that I am teaching the O-Line I would really like to incorporate the LEV sled more. Currently, we have it pushed up against a building wall so it wont move. What do you see as advantages/disadvantages of each sled type? Also, should I keep the LEV sled on the wall or move it out so it can be pushed?

Thanks in advance