I am sorry for your unpleasant experience using AppBuilder.
In order to investigate your issues further and try to fix them I will need additional details about them as they are not a common case.
Would you elaborate a bit more about your freezes? Do they happen constantly or just at the start? Do they pass after some time?
A short demo would be appreciated.
Do you find any errors in your Output pane
What is your system configuration?
Are there any logs from our Windows client in %localappdata%\Telerik\BlackDragon\Logs folder?
Please open a private ticket
and attach them there.
As an alternative I would suggest trying some of the other clients and tools
I look forward to hearing from you.