We've tended to bounce between Ford and VW group cars over the years, currently having a Fiesta and a Mii.
The Fiesta is a current (Mk 8) 1.0 Ecoboost 140 and the driveability is very good throughout the rev range, so I don't doubt that a higher output version of the 1.0tsi would do likewise. I guess VW group don't need to as they have the 150ps 1.5 which they can fit in the
Ibiza when/if they feel like it!
In terms of reliability, the ecoboost has had problems with cooling, particularly on early Focuses, but a new hose layout seems to have sorted that. Another issue is really down to poor maintenance. Failure to regularly change the oil and/or use the specific recommended oil, has led to instances of the oil pump becoming blocked with debris from the timing belt which runs in oil and can start to break up if oil changes are neglected. The latest version of the engine in the Mk 4 Focus has gone to a chain cam drive, I assume because of this issue.
The previous Fiesta had a 5 speed box which was never really intended to be used with a turbo engine, and the 140ps version has suffered synchro issues. The current version has a stronger 6 speed which (fingers crossed!) seems ok.
One tuner (Pumaspeed) has been running one of these engines at 200ps plus for some years, with standard internals and no reported issues other than (unsurprisingly!) the aforementioned gearbox issue. They offer a 6 speed box conversion for the earlier cars - a few owners have done a diy job.
Incidentally I've tried to persuade the Mrs to upgrade the Mii to an Up! Gti, but no success so far!