ORIGINAL: Dr1Driver
I started on a Northwest Aerodynamics .40 trainer with a flat bottom airfoil. After I crashed it due to an instructor's inattention, I built a Sig Kavalier. This is the plane I soloed on. I found it MUCH easier to land, especially in wind. The semi-symmetrical airfoil allowed better penetration and less ballooning.
Which is better? To each their own, as they say. Planes like the Goldberg Eagle or Great Planes PT 40 are VERY gentle, slow-flying planes that are excellent trainers. A plane like the Avistar is faster and less forgiving, but it penetrates better, doesn't balloon as much, and isn't affected by the wind as much. Both types have their good and bad points.
Ya pays ya muny an' ya takes yer cherce.
Dr.1
Without starting a dogfight, semi-sym (or sym) airfoils don't penetrate any better than flat bottomed airfoils, nor are they faster. Penetration is a function of drag vs available power. The Avistar is relatively small compared to the majority of 40-size trainers & is also a bit cleaner due to its lower cabin height -- its better penetration stems from that.
It has less dihedral than most trainers, which makes its ground handling a lot easier in cross winds. This also helps in flight, to some extent, when there are gusty winds.
The higher aspect, semi-sym wing, plus near shoulder-wing configuration and relatively light weight result in an altogether faster and more agile aircraft than a standard trainer. The speed is easily controlled by the throttle, but the inherent agility is always hiding in there to catch an unwary or underskilled student. Compared to a standard trainer, things happen much faster with an Avistar -- both good things and bad things.
I like it a lot, but if we are speaking in generalities, it wouldn't be my first choice for an unknown student.