Here is recent review of 10 popular concordancers, published in Corpus Lingusitics and Linguistic Theory 2/1: 107-127 (July 2006):
http://www.daniel-wiechmann.net/downloads/prefinal%20draft.pdf
Note that this PDF is the pre-final version of proof pages which may not have been corrected.
http://www.daniel-wiechmann.net/downloads/prefinal%20draft.pdf
Note that this PDF is the pre-final version of proof pages which may not have been corrected.