DA40: Nice flying aeroplane. Very comfy cabin, and can be spec'd to VFR, traditional IFR or glass cockpit. I have experience with the 1.7 Thielert which has caused us, and a lot of others, a lot of grief. The 2.0 engine is a lot better, apparently, but is downrated to 135 HP (same as the 1.7) to save rewriting/recertifying the POH. Later models use the 155 HP 2.0s engine or the Austro. I would get one of those, since 135 HP is really underpowered. It cruises just fine thanks to the slick airframe, but short field and climb performance leaves a lot to be desired.
Long wings and a castoring nosewheel makes it a handful to handle on the ground though. Some people get used to that quickly and maneuver the DA40 in the tightest spaces, others struggle.
Jet-A means that fuel costs are more than halved compared to 100LL, but you will have other costs. The replacement of the gearbox damper in the Thielert is one of them (although I think Austro uses a different system which lasts longer).
Oh, and it's again a four seater so it really doesn't seat four adults with a reasonable amount of baggage and fuel.