We use this weekly in our studies and are seldom disappointed. The convenience of looking up the english word and finding the greek is great for those of us who want a simple tool. We use other greek tools as well but this one is always referred back to as well.
Vine's Complete Expository Dictionary of Old and New Testament Words for me is second best to the Concordence. I've purchase several Bible dictionaries over the years and was not as pleased as I was after purchasing Vine's.