2009 Gen 3 Prius purchase

Hello there, I'm new to the forum. We, a family of three (one little daughter), are in the market for a Prius. The choice for a Prius was made after months of consideration. We need a reliable, comfortable, fuel efficient car for a long period (5+ years). Eventually it was a battle between Peugeot 308 and Prius, I personally don't trust Peugeot in the reliability department. I live in the Netherlands, so model names and prices may be different in the USA.
Initially, we were set on the Gen 2 Prius. I personally don't care about looks much, but my wife didn't like it. It ticked all our requirements though, so Prius 2 it was. We went out and did a test drive in a 2009 Prius Business edition. It was good, comfortable, but my wife still thought it was ugly and I felt it was lacking in power too much. Now I don't expect a Prius gen 2 to take of like a jet, but I was still disappointed. These cars average at 9000 euros.
We made this clear to the dealer, he asked us whether we would like to try a 1.8 (so gen 3). Why not? He brought us a car, a 2009 Prius 3 Dynamic with a solar roof. My wife obviously falls in love with it, and I thought the interior and raw power were a couple of steps above the Prius 2. These average at 11.500 euros.

Now the obvious choice for us would be the Prius 3, we both liked it a lot more. I still have my reservations though. Is there any such thing as "design maturation over years" in car models? What I mean, is it smart to buy the first iteration of a new model (2009 Prius gen 3)? Is the engine just a bigger, badder Prius engine, or is it a new design? As a final question, can I expect the same superb reliability of a gen 2 from a gen 3? I'd really like a car that is tested and tried, that's why the 2009 Prius 2 still tickles my mind. The engineers had years to mature their designs for the Prius gen 2 in 2009.
Is this "design/model maturation" idea I am having completely idiotic (i.e. should I just b uy the 2009 Gen 3)?

As a reference: 2010 Gen 3 Apiration (second tier model) goes for 10500
2010 Gen 3 Dynamic (no solar roof) goes for 12500/13000

 

I see my thread got moved, I thought it was deleted I only named average prices as a reference.

Thanks for the reply. I would have thought they'd improve each year, doing little tweaks here and there. Now that I think of it though, that wouldn't be very practical since you can't suddenly change a massive production process I simply have no clue how car designing and manufacturing works.
I've read more into the Prius 3, it seems to be an evolution/upgrade of the Prius 2. So I guess that would be the best choice for us since we are fine with the price difference and we like it more. What is troubling is the lack of user reviews here in the Netherlands for the 2009 models compared to the 2010. Could that be because in 2009 there was an overlap between old and new, so the 2009 Prius 3 sold less than the 2010 model?

Such a beautiful and reliable car though, we are still thinking about our test drive.