The newer style condensers are definitely more efficient. That's why they went to them because of poor cooling from the old style when using r134a. R134a isn't as good of a refrigerant as r12 is, so if you can design the system to work more efficiently, it's always a good thing. That's not to say an old condenser won't work with r134a. It's just You'll have lower cooling capacity in certain scenarios. Like when stationary at idle. But, I've added electric pusher fans to a system that had those issues and they were resolved.