Coming from a guy with an NA R32 (with R33 RB25DE S2 engine), they seem pretty rugged and manouverable, more suited for tracks. As the strong points are weight, size, and wheel base. Even then, the R34 is equipped with better LSD and tech? (unsure) so lap times should be similar. Also the new engine has more torque.
Fuel wise I can get about 9-10L/100km with a bit of dose every now and then. So the refined RB25DE Neo should get a bit better.
Comfort wise i doubt it's as good as an R34, even the interior should be falling apart slowly by now. However i do like the seats as you can adjust the sides to hold you firmer. You should be able to find a clean R34 MUCH easier than an R32, let alone a non turbo one, furthermore a 2.5L.
Also with an R32 you will need either lots of time or money to fix whatever screws up as it is considered an old car.
All these points indicate an R34 is a better choice for you.