I am using the older shape version 2007. Bought it 14,000 driven and I have now driven it to 95,000.
If you are used to driving a bigger car then you won't be comfortable in a hatchback. But upgrading from Cultus, Alto Mehran, this car is very good. Good smooth drive. I have been to chitral, sawat, kalam on my ride.
I drive daily from DHA2 to ISB and back. Total route 60+KM. Its very good and economical for intercity. I usually get around 15+ kmpl. I drive usually aggressively. On long routes, if you go above 120km speed, don't expect good fuel economy. If you are between 100-120, you can get somewhere between 17-20 kmpl economy.
Answered above
Its definitely not underpowered. With 5 passengers with trunk full of load, I have done 140+ on motorway. If you need more power, get 1300cc version
Body parts are very expensive but available. Engine parts are not as expensive. If you have a trustworthy mechanic, he can get genuine parts for you from his contacts easily. Regular maintenance parts like air/oil filters are same as vitz. Driven my car from 14000 to 95000 and Alhamdulillah car has not given any engine problem so far. Car han accident in which driver side door and fender was replaced. Replaced door costed 14k 
Not sure about prices of current versions. 2007 model in Islamabad is going for around 8.5 to 9.0 lac. I bought mine in 9.5 three years ago. So you can expect to loose around a lac in 3 years.
Its not dual vvti. Older passo has 4 speed Auto transmissions. Newer models have CVT transmission
AC is good in running car. Not so good in stand still of traffic jam.
For me, yes it was worth buying.
Thanks
