i have the herron, and had considered the groove. while i have not heard the groove, it's rep is very respectable. i have enjoyed the herron tremendously. it is in a tubed system, and seems to have great synergy with the rest of the stuff. the groove and herron are both totaly lacking of contols (you must order specific boxes for different loads), which i appreciate, minimum interference with the signal. good luck and enjoy it.
