With the current release of Thrive Architect, this is now a very close competition.
If I were building websites for clients, I would go for Beaver Builder because it is very reliable will won't cause you any headaches down the line.
Also, Beaver Builder is a real page builder with full website builds in mind.
But if I was making just a few websites for myself, you can't beat the value you get from Thrive Architect.
It is priced better, and it has almost every feature you could want.
Also, Thrive Architect has excellent marketing-focused elements.
Keep in mind that to use any of the templates in Thrive Architect, it will remove your theme's header and footer on those pages.