I think all of those are good areas and all of them have different characteristics.
However, I think that one advantage Lenader and Cedar Park have over Round Rock is that if you need to get into Downtown quickly, both of those cities have access to the commuter rail.
The Capital Metro Red Line has a stop at Lakeline Blvd and another in Leander, that allows people to travel to downtown without all of the traffic. I believe the trains are wifi enabled, so it is possible to work or browse the internet while traveling.
I think that of all of the areas you are considering, Cedar Park offers the best options. Cedar Park has many commercial businesses there, including Lakeline Mall, an Alamo Drafthouse, restaurants, medical centers, an HEB Plus, coffee shops, etc. Additionally, they have a well developed park system for a city their size. Between Milburn Park, Veterans Park, and Cedar Park Town Center there are plenty of options for everyone.
Avery Ranch is a nice neighborhood also, however the homes can be pricey. Be careful with the property taxes also, as some sections of Avery Ranch are in municipal utility districts that have separate property taxes.