is this a good buy?

Depends. 14k isn't all that amazing for gold, but I'd guess that it'd be like $150 for the pendant itself, gold-wise. So, then you have to ask yourself, "Is .20 carats worth the $500 dollars?" It seems like it's priced pretty fairly, imo, because 1/4th carat pendants start at about $450, and it's the design you want..
 
It doesn't really say what quality the diamond is, if I were you I would call and ask for that information. Ive never bought any jewlery from macy's - but I actually heard and interesting thing when i was in the store last weekend. I saw a jewlery cleaner by the fine jewlery but everyone was so busy helping others I decided to take a look at the watches, and I asked the SA if she knew about the cleaner and she's like oh no - the jewlery department is seperate, they are privately owned so their SA's dont know about anything in macy's and macy's SAs dont know anything about the dept!

WEIRD! I don't know if it was that particular store, or if that is the case in all macys!

But I do like they style of necklace, think it's really cute. But again would call and get the stats of the diamond, id hate for you to pay almost 700 bucks and it be an i or less quality diamond, kwim?
 
I agree with the above poster. They don't list the diamond quality, and judging from what I've seen in the Macy's jewelry department, it's not too great.

It's overpriced.