I spent a very long time looking for one to replace my old Black and Decker.
Back in August I bought a ALKO SP5000 from http://www.mowdirect.co.uk/

It was expensive at £289 but it really does the job. It's very powerful, quiet
and takes anything from branches down to very thin twigs and chops them up.

It's quiet because it uses a type of cogwheel cutting system and not spinning
blades as per my old Black and Decker.

If you want more details e-mail me if it helps.