I'd heard the ME109's were pretty unreliable.
ME 109s were bloody good planes AIUI.
The fuel injection system on the ME109s was better than the Spitfire's carbs, it meant they didn't suffer from fuel starvation in dives. Spitfire pilots evolved the roll dive to compensate, but I believe it wasn't really solved until the invention of Miss Shilling's Orifice.
