I downloaded the trial of Air Server onto my late 2009, 27 inch screen iMac (non Retina) running OS X 10.8.5 Mountain Lion using the Airplay function on my older iPad 2 (haven't tried this with my large iPad Pro, yet) and I had no trouble with this app whatsoever.
My iMac's screen resolutionis set one notch down from its native screen resolution because I don't like the tiny menubar.
The trial won' t let me play YouTube videos, but it streamed some other video apps that I use, like TED talks, SNL video app, Vimeo app.
Oncreen response of my iPad on my iMacs screen was nearly flawless when just navigating my iPad.
The videos do not fill my iMacs screen, but takes on the full screen mode of my iPad.
Video quality on my non-Retina iMac was very acceptable, but not quite as sharp as my iPad.
Still very good, though.
If there is any video/audio lag, it was negligible as just watching my iPad screen from my iMac audio and video really looked to be in sync.
I wasn't comparing any lag from directly from my iPad to my iMac when watching video.
Why would I care about that issues?
As long as the videos play clean, clear, smooth and in sync to my iMac!
This app works great on my older iMac running an older version OS X.
Not seeing the issues you seem to be experiencing.
I am probably going to purchase this app!
This was the very first time I have experienced the AirPlay functionality on my older iMac because my iMac was too old to support it!
I like having this ability!
What are the real issues with Air Server on your MacBook Pro?
What year and model is your MacBook Pro?
How Much RAM installled?
What are you using for a WiFi router/MODEM?