I generally prefer the default Blizzard Action Bars because when you get into a vehicle it shows the energy or whatnot that Blizzard wanted you to see. Bartender4 and Dominos are very popular and I suspect most people probably use one of them so I’ll explain the underlying difference between the two and how it can impact raiding.
Here are the crib notes for the 3 varieties of action bars:
The Blizzard default action bars are extremely large and take up a lot of valuable real estate on your screen, but since they’re designed by Blizzard they won’t break during reloads in combat and never need updating. They also show exactly what Blizzard wanted you to see.
Bartender4 creates its own frames and keybinds to them. This creates issues if the addon breaks due to a major patch since all your keybinds set up for custom Bartender 4 frames.
Dominos re-uses as much as possible from the Blizzard code so when the addon breaks all your keybinds are still bound to the default action bars and saved server-side. Between Bartender4 and Dominos this is the best-selling point in my book. There are reports of Dominos being easier on the almighty cpu usage since all it’s doing is moving Blizzard’s action buttons versus making new frames.
Bottom line: In case of disconnect and you have to come into a fight IN COMBAT then default Blizzard action bars are best, dominos is next best, and bartender makes you a worthless raider since you can’t create new protected frames in combat. As far as functionality I found that dominos and bartender4 are almost identical enough not to worry about anything.