You're not asking too many questions.
The Antennas Direct DB4e is an excellent antenna. The DB4e is one part of the 'premium' antenna system I described earlier. However it's intentionally designed to receive real channels 14 through 51. If you install
only the DB4e, you'll not have much chance of receiving:
Real CH-9, KCTS (which carries PBS in HD, V-Me in SD and Create in SD)
Real CH-11, KSTW (CW in HD)
Real CH-13, KCPQ (Fox in HD)
If you have room to install both the DB4e and Antennacraft Y5713 as described earlier, you'll have a higher performance antenna system.
The ANT-751 is a compromise that is driven largely by the assumption of limited space and budget.