Having hire cars all the time, gives a great chance to drive most new cars, and I have to say the Mondeo has evolved much better than the Vectra.
The Mondeo is very plesent to drive, comfy, and solid feeling, the Vectras however feel more plasticy, and more cheaply put together. The last Hire car I had was a Vectra - which was considerably better than the Zafira before that, but neither where as good as the New Mondeo I had previous to them....
But again be fair, you are comparing a new generation car against an old generation car in comparing the new mondeo to the Vectra.
The build quality in both of Scott's last-gen Mondeo's was quite solid, but it was utter shite in terms of looks, it was so plain and the plastic felt, and looked so cheap, it was never worth the money Ford were charging for them.
Maybe with the new Mondeo, Ford have realised that a big plastic lump does not make a dashboard, and if so, what's to say Vauxhall havent?
Personally, for a new car in this class, it would be an Accord for me hands down anyway