I'm almost afraid for someone to answer you on that one!... Husqvarna Group own Flymo and McCullough. The Husqvarna 105, Flymo 1200R and McCullough models all use the same body and chassis if you look at them. I read on a pistonheads thread that alot of parts are shared - and stamped Husqvarna.
The thing that tipped me to the Husqvarna is that its is considerably heavier than the Flymo ( which sells as low as £435 at times on amazon). My unconfirmed logic is that the motors or parts somewhere must be engineered better. Its 9kg (ish) compared to 7. But... the controls are the same, wheels, body.
My 105 is great - but did I pay x2 the price for the name?...