I purchased a Redback E142F in early September and so far have made 3 cuts of our c.100m2 lawn on only 1 charge of the Lithium 6Ah battery. It's very efficient and powerful yet quiet.
The only issues I had were with the assembly. The user manual has very small illustrations and without much detail. The cutting height adjustment mechanism was completely seized up with black paint and too tight couplings. I had to free them up with WD40 and released the couplings before it would adjust to a sensible cutting height. The grass box is large and easily takes the grass from a complete mow of our lawn.