Calor Gas 4.5kg regulator gauge

[cubensis]

Hello all, i was wondering if anyone had ever used one of these regulators that incorporate a gauge?

http://www.discover.co.uk/electrical-ga ... -regulator

... and if so how good or bad they were?

I'm after finding a regulator that will give me a steady and accurate display of how much gas i have left and was wondering if this was the best thing out there?

I believe the stick on strips that change colour are pretty useless. The alternative is to carry two 4.5 kg bottle all of the time but i'd much prefer not to have to do that, any help advice or tips would be appreciated!