Congrats on the approval!
I am in the process of building my credit, and what has really stood out about the Zync is the spending ability. My revolving bank CCs started off with limits of $300 and $400, which meant I had to pay off my cards several times each month, and sometimes couldn't use them for larger purchases. For scoring purposes my utilization was horrible as a result. The Zync saved my be allowing me to actually use my card to pay my expenses while not killing my utilization. I've been extremely happy with the card and customer service.
The Zync rewards structure can be very good (in-line with at least Gold) if
1) You select packs and use them wisely. I think the best four packs are Restaurants, Travel, "Connect" and ECO. They all give you double points (on up to $5,000 in spending) in each category. If you put all your flights, cable bills, phone bills, restaurant spending (which is substantial for me in New York City) and "green spending" (works at Whole Foods) on the coard, you can accumulate points quickly.
2) You use the Zync card for a year, then apply for another Amex charge card (Green, Gold, Platinum) and upgrade your Membership Rewards Express points to the regular program. At that point, continue to use the Zync for purchases where it is an advantage. While some Amex cards are better for travel purchases (I think one of the Gold cards offers 3x points on airfare), no other Amex cards to my knowledge offer double points on restaurant or connectivity spending.
3) You value looks in a card. The Zync is arguably the best looking card Amex has.