Had to drive 200 miles on an Astra space saver once, 2/3 of which was motorway. Takes a bit of getting used to especially under braking. Worst bit was doing 50 mph on the motorway and getting tailgated/honked at by HGVs who did not realise why I was only doing 50 (space save on front near side). Still, better than a can of glue....
If manufacturers did a risk assessment on the use of a space saver by their customers they would surely conclude that a full size spare should be provided. I know it's no longer in fashion, weight/C02, changing wheel on h/s and all that - at the very least they should provide a 'Limited to 50 mph' sign for you to put in the back window.
