For now I think both Aston Villa and PSG is in good shape and form and they can defeat any team that underrates team but since they are to play against each other it's going to be a big fight, PSG stands in a better position to win looking at their performance and how they played against Liverpool in both legs, if PSG repeats that dominance against Aston Villa they will be able to defeat them but if they give Aston Villa a little chance Aston Villa with their sharp strikers will not fail to make good use of the opportunity to defeat them. I am rooting for Aston Villa to qualify ahead of PSG this is my own prediction though.
Aston Villa is a big surprise in Champions League this season and they are a newbie here but they have danger of a newbie and underdog. They are not fearful of anything and simply are fighting and enjoying their memorial Champions League season. No fear will be their strongest advantage to fight against PSG that in contrast have more experience in Champions League.
PSG has spent a lot of money to build up their squad mainly for Champions League and they have yet succeeded winning any Champions League title. This season seems to go well for them, by meeting Aston Villa in quarter finals, they have good opportunity to move to at least semi finals. This fixture and the road to final match actually motivate PSG a lot in two quarter final matches with Aston Villa. They are not too far from a second final match in Champions League after many years.
Aston Villa is a surprise in the Champions League this season but I think they also have enough luck to get this far. When many big teams had to face each other in the round of 16, Aston Villa instead met Club Brugge. Facing PSG will be a real test for Aston Villa, and if they can get rid of PSG, then Aston Villa deserves to be considered a dark horse. If we talk about opportunities, I see PSG still being much better than Aston Villa because PSG had to get rid of Liverpool before getting here and they got that very hard. I think Aston Villa is still below Liverpool, so PSG should be able to beat Aston Villa.