I personally feel that splits are superior for gaining mass in most cases, but experience/training age will also play a role in determining whether splits or TBT are a better choice.
When I first started training I did a full body routine (1 basic mass building movement for each major muscle group done for 3 sets of 8-12 reps) done 3 times per week.
For beginners I personally like TBT (Rippetoe’s “Starting Strength” is a great beginner TBT program) because it allows for a lot of practice on the “money” lifts.
Like CT said in his recent article, resistance training definitely has a motor learning/skill component that needs to be developed first and foremost. The more you practice a skill (more frequently) the faster you will get “better”/more neurologically efficient at it.
But, once you pass a certain point, I feel it’s best to start splitting your program as to allow for more recovery (since your improved strength will allow you to tax your nervous system/recovery systems more). You don’t have to go right to a 5 day split though. Two way splits (push/pull, upper/lower, etc…) are a good next step.
The stronger, more experienced and more capable of stressing your CNS/recovery systems you get though, the more you’ll have to either split your routine, or decrease your volume to be able to continue to progress.
Now, I’m not saying that you can’t just jump right into a 5 day split right off the bat. I know quite a few people who did just that and grew just fine on it. The above is just my personal preference.