Battery life should be pretty good. It seems Priuses are good for about 10 years before the battery falls off, and you have that ten years of R&D on your side. Should be better with a 2013 and up, because the battery went lithium ion.
I generally like mine, but it's not perfect.
The S+ button (2013 feature, kinda like a hybrid KERS, dumps more battery for a short boost of power) doesn't really work on a LHD manual car - the S+ mode cuts out if you lift, hit the brake, or drop below 19 MPH. The button doesn't react to a quick tap, and it seems to take a moment to think about engaging. It's also low on the right side of the wheel, under then hand you use to shift. So, on the CVT, get to 19 MPH, hit S+ and push the pedal in. On the manual, get to 19 MPH, hit the button, shift and have it turn off, move you hand back to the wheel, hit the button, shift before it engages, watch it turn off, repeat. If you have a good long pull in a higher gear, it's nice, but it is completely useless under 40 for street driving. There will almost always be a reason for it to be off, and if you can't rely on it, what's the point?
There is little clutch and gas pedal "feel," so it's a little hard to drive smoothly until you're used to it. The three drive modes can make this worse.
It lacks some of the cushy features of its contemporaries. For example, even with automatic headlights, those puppies are off when you take the key out - you can find your own damn way to the front door. The bluetooth on anything without nav won't get you Siri, Google Now, or whatnot. The remote doesn't roll down the power windows. The key is huge, sits on your knee, and there is no keyless option.
It is really fun to drive though. It feels light, and has a fairly crisp turn-in. It shines on steady highway driving. Some people get great MPG, but my usage is heavy on stop-and-go and aircon, so I'm averaging about 32 MPG across my ownership. Trips do better, and I can get into the 50 MPG range. When I'm driving aggressively on short trips with lots of stop signs, I'll see 25 MPG. I really like the seats.
Oh, and there is an A/C vent in the glovebox, so you have that.