Really?
The Vibe's Toyota running gear made for economical operation. A 2003 base Vibe with manual transmission was rated at 7.7 L/100 km (city) and 6 L/100 km (highway), while choosing the automatic drove consumption up to 8.3 L/100 km (city) and 6.4 L/100 km (highway).
That seems pretty impressive to me, especially given the matrix/vibe isn't that small, as in Yaris/Fit small.
I looked at the Matrix/Vibe when buying our P5. The odd driving position and so-so handling turned me off. Otherwise, I think they're great cars.