The scenario we played depicts a hypothetical situation from the AD1053 Battle of Civitate (where the outnumbered Normans beat an Italian/German alliance in southern Italy). Half a dozen Swabian heavy infantry are isolated on a knoll with some trees and brush for terrain; the Normans are trying to kill the Swabians before a Lombard force can rescue them.
The Normans set up one force in melee with the Swabians, and a second force of cavalry as a screen blocking the rescuers. The armored Swabians were pretty tough, and held out for a while despite being outnumbered and surrounded (and despite my initial placement of them, which probably could have been better); however, the Norman horse delayed the Lombards long enough that only one wounded Swabian escaped. The Lombards did manage to kill the Norman lord, though, and claim a moral victory.
The rules are readable although somewhat ambiguous on several points. Two things I found odd: a) there are no morale rules; in our game, there were high casualties but no one retreated more than one space; b) each man is represented by two or three double sided counters, and you have to replace the original Mounted Intact counter with Mounted Wounded, Dismounted Intact, Dismounted Stunned, Dismounted Wounded, or Dead. The task is not made easier by the counters being thinner than I'm used to. There are a couple other quirks (Byzantines should be skutatoi, not hoplites) but nothing major.
Given the game cost (~ $100) as compared to skirmish miniatures rules such as Pikemen's Lament or Lion Rampant, I don't think I'd buy a copy of Guiscard; however, I'd certainly play it again.