Ortron and I finally managed to sync schedules. He rolled out the IG tank army again ( a total of 6 infanty stands) which included 2 Superheavy companies (Storm Hammers, Storm Blades) + a Storm Sword. He also had a Leviathan, plenty of arty and his obligatory Hydra/Marauder combination along with some extra tanks. The core of my Eldar army was pretty standard (Defender, Jetbike and Spirit hosts + Tempest support) but I took Revenants and Unicorns to test. I also forgot my DW templates so had to leave my arty behind and "replaced" them with Scorpions. So, the battle field was set:

First turn and the Eldar used their mobility to capture most of the objectives and generally occupy good field position. The Eldar left flank looked to be where the battle was going to be decided. Pathfinders grabbed an objective inb some ruins at the crossroads on the IG side, and they were supported by the Defender and Spirit hosts plus the Revenants. Across from them sat the entire IG artillery, coverered by Hydras and the Leviathan, and with a company of Storm Hammers rumbling down the road.

The Guard were counting on the Storm Blades, Destroyers and Hellhounds to take the Eldar right. They faced the combined firepower of a Tempest squadron and Nightwings, with the Avatar and his bodyguard of Scorpions advancing. The Superheavies waded through this masses firepower without loss, though 2 of the tanks took heavy hits.

The rest of the first turn followed the same pattern, with the IG tanks shrugging off hits while their artillery pounded the advancing Eldar to bits. By the end of the turn 3 super heavies were damaged, but the only loss the Guard had taken was one Hellhound. The Eldar had conversely suffered pretty heavy casualties. The only bright spot was the Revenant repairing the leg damaged by the first shot fired at it.
Turn 2 started as the first ended, with the Imperials taking the initiative. The Eldar grabbed another objective while the Storm Blades moved in to contest the right. A detachment of Swooping Hawks dropped down behind the Imperial artillery. The Imperial commander responding by turning the ponderous Leviathan to face this threat. The artillery's fire was again telling, smashing a building on the left, killing the Guardians inside and exposing their Falcons to fire.

A minor bright spot was the destruction of a Marauder by an excellently placed needle rifle shot. The Marauders flew on and strafed the Revenants but with less success. The Eldar managed to destroy some minor units but again the Superheavies shrugged off hits galore. The Imperial firepower smashed unit after unit of Eldar troops. The Leviathan unloaded everything on the Hawks but when the smoke cleared one stand remained. The Eldar troops celebrated their miraculous survival by lobbing a krak grenade through the open hatch of a nearby Bombard.
Close combat was better as rampaging jetbikes shredded a number of Destroyers, Chimera and Hellhounds. Despite this, but the end of the turn two of the Eldar hosts were broken and some of the Eldar lost their nerve and began to retreat.
Turn 3 and the Eldar tried to cement their hold on the battlefield. The Avatar decided it was time to take matters into his own hands and flung his spear clean through the armour of a Storm Blade, finally destroying an Imperial super heavy!
The Guard decided they wanted the Pathfinders cleared off the objective they'd been holding. The doughty scouts held their ground, though I can guess what they thought when they saw this:

The Eldar at last managed to land some telling blows and one by one the Storm Hammers were turned into crumpled wrecks. However, despite the firepower of the Tempests and the Nightwings directed at them, the Eldar couldn't break the Storm Blades. Luckily however they managed to retain 6 objectives.