I had a 2009 Scion xB. Love the room, power was good, but between the generations I'd take the 1st gen any day, as long as it's a 5MT. Always liked the look of the 1st gen, and the better fuel efficiency is a huge bonus. I can live without the extra power. Heck, I commuted on a 49CC scoot for 7-8 months, so for me MPG>WHP all day long. Overall the 1.5L 1NZ-FE in xB1 is a much more reliable and efficient unit than the 2.4L 2AZ-FE in xB2. To me the 1st gen is like a legal chance to own a Kei car with a big block lol. Considering JDM kei cars only had 0.6L of displacement. We'll call it Kei+.
The funny part is, the Prius 1NZ-FXE is an absolute dog - even a loaded down bus can out-accelerate me. Even worse than a Nissan Quest(Ford era, not the Altima-based, adapted for America Nissan Elgrand with the VQ35DE) from the 1990s or a Mercedes 240D. The Echo/Yaris/xB using the non-hybrid 1NZ-FE pulled above their weight.