I have just built a Gryphon in the last month and am dead chuffed to date.
Couple of days on the singletrack at Brechfa last week including the red trail (goes round the berms like its on rails and much more nimble than I was expecting) as well as long forest road / bridleway expeditions.
build spec:
Gryphon large frame;
American Classic All Mountain 29er wheels with (tubed) Conti 2.2 Race Kings;
Middleburn R7 cranks with Uno 32 chainring up front and 11/36 outback (1×10)with XT rear mech;
STI 105 levers / shifters with BB7s;
Ragley Luxey bars with Planet X stem and seat post etc.
Did I say I was well chuffed!