Something that Jai didn't point out about the 'ancient technology' of the Uno Turbo is that it is a multi-point injection system (one injector for each cylinder), which is more than can be said of the much newer 8V Punto models. Also I think the engine block dates back to 'only' 1969

But, of course, there are many changes.
I can't really think of anything 'ancient' about the Uno Turbo that holds it back compared to some modern development. Maybe not-having variable valve timing or variable-induction-length, both of which aren't relevant to a turbocharged engine? Meanwhile, Ford were still putting a pushrod motor into the Ka about ten years after the Uno Turbo was made (and 30 years after the SOHC FIAT motor made its debut in the 128), so surely that deserves the 'ancient' comment more? Maybe even the Uno 903cc deserves an 'ancient' comment since that had a pushrod motor - but FIAT came up with the goods by 1986 with the FIRE.
The Uno Turbo has a thoroughly-engineered (witness the oil cooler, piston underside spray-jets, water-cooled turbo, even an injector cooling fan though most are now removed!) and tough little engine. I actually think it is the most reliable of the Unos, not for its simplicity, but because of the quality of the engineering. Stuff is just bigger and better than on the other Unos - e.g. the ignition ECU is a proper mapped type with crank/flywheel sensors, not some little finned box on the distributor, the alternator is bigger and stronger, with an air-cooling duct, and the radiator takes up the full width of the air intake. I reckon the development engineers pulled out all the stops and fitted the parts that were kept out of the other models to save money!
I get an average of about 32-35mpg out of my Uno Turbo, with as much as 53mpg averaged on a long and gentle trip. When the economy is that good, you have to measure it against the performance available and consider the depreciation cost (loss in value each year) of other newer, possibly more fuel-economic cars. To me, the Uno Turbo seems an economical car when you get 0-100 in under 8 seconds and you take into account that it's hardly losing value at all these days.
-Alex