After recently perusing the Alpha Strike Companion rules for four-legged/quad mechs (p.40) it seemed to me that quads cop it a bit rough. Of particular note was the 90 degree forward firing arc. This is even narrower than the 120 degree forward arc under Total Warfare rules and I imagine it would make quads quite vulnerable to attacks from their flanks.
Not only do quads get a narrow firing arc, they lose other advantages they have under Total Warfare Rules. Lateral shifts & piloting skill roll modifiers generally don't apply in Alpha Strike. It is however noted that if certain optional terrain rules are in play, quads do get a -2 to control rolls in Alpha Strike.
As such, it would seem to me that unless you are using the optional rules for quads in conjunction with some optional terrain rules, quads cop a narrow firing arc without any benefits to offset this disadvantage. This seems particularly rough when there are vehicles without turrets that get the standard 180 degree firing arc.
I would note that I'm just pondering the rules here and haven't actually tried playing the quad rules. Anyone given them a go, and if so did you find the 90 degree firing arc a big disadvantage?