Cheap 3kW inverter

I see that Maplin are doing a 12V 3kW inverter for a penny under £250 £350*. It's only modified sine wave, so that might restrict what you can successfully connect to it, but it seems like a lot of watts to the pound. It even has a remote power switch.

This is Maplin's photo - I'm sure they won't mind me posting it here!

I have no connection with Maplin - I just thought this might be of interest to my fellow boaters.

Is it washing machines which object to anything which isn't a pure sine wave? How do 230V fridges and microwave ovens cope with modified sine wave mains? Electric chain saws?

*update... This was a "deal of the day" offer - it appears it was for sale at the lower price for one day only.