Thanks juliusz there's some good info there. Always a mine field choosing the right bit of kit, especially with the price tag attached.
The thing I like about the Eheim e range was the controllable motor speed. Say for instance I wanted to use it on a much smaller tank the option is there to slow the speed without just part closing a tap. Energy saving and less strain on the impeller. I know what you mean about more parts to go wrong, but you wouldn't believe how many things that you already have just in your house are Micro processor controlled. They're everywhere. And the majority of the time it's not the circuitry or IC that goes wrong. Unless of course you buy cheap shoddy Chinese.