The Gtech ST05 14.4v Cordless Telescopic Grass Trimmer looks pretty impressive. Powered by a rechargeable 14.4 volt Li-Ion battery you are not restricted by the length of your mains cable.
Unlike other strimmers the Gtech ST05 does not use a plastic line that winds onto a reel. Instead it has a replaceable spear shaped plastic blade similar to ones used on some electric lawn mowers.
The video below demonstrates how versatile the Gtech ST05 is.