All in all then, the on-board computer is pretty much useless!
Compared to the trip computers on most other cars, it's a pretty atrocious effort, isn't it? No instantaneous MPG, crap average MPG resolution, no 'split memory' function, and the miles remaning indicator disappears right when you need it the most.
That said, it's still better than no trip computer at all. When I was looking at new cars in 2002, you were still hard pushed to find any in the Lag's market sector that had trip computers, let alone ones that had one from the base model upwards. Of course, trip computers are much more common now (even the Pug 207 hire car I had the other week had one) and the Laguna II's computer really doesn't cut the mustard compared with the capabilities of most.
To be honest, I'm surprised they didn't improve the trip computer functionality when they switched from the Sagem to the Magneti Marelli instrument cluster in 2003-ish. That they've carried it over onto the 2005 phase 2 model is ridiculous.
The resolution thing seems to be peculiar to the Laguna though. ST says that the Megane doesn't do it, and I'm pretty sure that the Clio doesn't either.