Alot of head space might be good for a primary fermentation. Having all that room will not create the need for a blowoff tube. In a secondary, however, I personally wouldn't want to have all that room unless you could purge it with CO2. Another concern I have about a container such as this is the fact that it could possibly create off flavors from holding all that LME. Also, does it have a hole in the top where you could insert an airlock?