I tried out my army list against a Grey Knight (I hate the Silver Knights!)
5 objectives in total, 1 in the centre and 1 roughly halfway between the centre and each corner (board was only 3ft wide, 4ft long) I think he had Draigo, 5 Terminators, a 7/8 man PA Grey Knight Squad (1 Psycannon/Incinerator) and a 7 man PA Grey Knight Squad (1 Psycannon/Incinerator) with Rhino. Everyone had Psybolts (i think that's what they're called)
The Bikers and Tactical Squad sped forward, their combined firepower wiping out the 7/8 man Grey Knight Squad on turn 1. The Grey Knights stun the Razorback
My combat squad with Multi-melta and 4 normal marines blew up the Rhino turn 2, the marine with Psycannon/Incinerator dying. Draigo is reduced to 2 wounds and 1 terminator is killed by my Tactical Squad/Biker Squad.
Turn 2/3 Draigo left the Terminators and went after my Bikers, leaving them with the sergeant, a meltagun-biker, and a wounded Attack Bike. The Terminators wiped out the Tactical Squad in combat, who had already lost 2 of their battle brothers to shooting.
The Razorback lost its Heavy Flamer and was immbolised on turn 2/3.
Turn 3/4 Vulkan/Orpheus and the other combat squad came out of the Razorback the turn after, their meltagun, combi-melta, heavy flamer and 3 bolt pistols killing 2. The Terminators killed 4 Marines after Orpheus and Co. assaulted them, but Orpheus killed the 2 left.
we had 1 objective each but didn't get to finish (and I was about to melt Draigo
He had the 6 Grey Knights in PA (on the objective) and the wounded Draigo left.
I had my Multi-melta combat squad (on the objective), the Combat Squad Sergeant, Orpheus/Vulkan, and my depleted Bike Squad (thanks to being reminded that bikes flee 3D6 not 2D6)
All in all, it was a good game, and I loved using Orpheus - all those Melta re-rolls (at 1 point I rolled triple 1's for my Bike Squad, which quickly became a 3, 5 and 6). I don't really think I could've done anything differently, the only thing that could have helped would have been a bigger board, where I could take advantage of my superior mobility.