Check out these comparison numbers!

The Gray Hoverman design is based on the Hoverman patents but we are waaaaay past that into a range of performance that beats any comparable commercial antenna (the SBGH smokes the CM4221, the DBGH smokes the CM4228) and any other DIY antenna project of similar requirements.

GH Gain Figures Vs. Similar Antennas

Channel-----4228---4228HD--PR-8800--DB-8---GH10-----DBGH

14--------------10-------11.2---------12.5------11------14.24-----14.34
19--------------12-------11.6---------13.7------12------14.74-----17.17
27--------------14-------11.7---------14.5------13.5----14.61-----17.83
35--------------15.7----10.9---------14.4------14.2----14.75-----18.26
43--------------15.7----11.1---------12---------15------15.30-----16.53
52--------------15-------11.7---------10.5------16------15.03------8.92*
60--------------14-------11.7---------10---------16.6-----NA--------NA

Notes:
* CM4228 is the original Channel Master 8-bay bowtie reflector (data from HDTVPrimer)
* CM4228HD is the new Channel Master 8-bay bowtie reflector
* PR-8800 is made by Winegard (data from HDTVPrimer)
* DB-8 is made by Antennas Direct (data from HDTVPrimer)
* GH10 is a Single Bay Gray Hoverman Gold Standard (data from j3d)
* DBGH is a Double Bay Gray Hoverman (data from 300ohm)
* * is for Channel 51 (antenna not designed for 52 and higher)

The announcement I made earlier today is about a new variant of the SBGH and DBGH antennas that also get great VHF-HI gain. It isn't on this table.