Sunderland are definitely having a great season. It's never easy for the teams coming from the Championship to have a good finish in its first season in the PL.
But they are doing it really nicely now by being in 8th place. They were even in top 4 earlier but of course they were going to drop down from there sooner rather than later.

Three teams promoted in this season among them against all odds, Sunderland is doing impressive job as they are currently at the 8th spot which is above many big teams, definitely a great job by them while Leeds United is in danger zone and Burnley already having their spot in relegation zone.
With their current level of performance, they have good chance of staying into good spot, it is good because now things have never been easy for them to stay at this level yet their squad is well balanced, and their performance is also good which keeping them at good spot.
By the way Aston Villa are still doing great by keeping themselves in top 4. Do you think they'll finish there?
For me, no doubt Aston Villa will be ending in top 4, their last few matches were not good still they were blessed with good results.