Hi,
that is a very good question actually.
To be honest the new Cleanup has been created using both approaches combined together. Which means that we took some features from the AVG PC TuneUp product, polish them a bit and then plug them to the newly developed "core" of the Cleanup product. There were also some features which we had to implement from scratch but they are at least using the know-how we got from AVG PC TuneUp and TuneUp Utilities products.
So the bottom line is that the new Cleanup shall combine the best of all of its ancestors using the know-how and technology we inherited from the AVG and TuneUp products.
Regards!
Avast Cleanup team.