Drilled or External Overflow?

[Bob]

I have had external overflow for almost 20 years...
The new ones are self priming...so if power go's off..they start atuomatically...
If this is your first tank...you will be moving up...usually a few times...this is where the external one pays for itself...I have seen a couple on here recently...one for 80 the other a 100.
They do not over syphon..overflow your tank...they work almost the same as a built in one....I speak from owning both....I still have my external one