We had it and used it a lot. We didn't buy a bouncy seat, so this functioned the same way. We were able to pick it up and move it around wherever we needed it. Plus, DD didn't like sleeping in the big, flat bassinet portion of the PNP at first, so she slept in the napper for the first 2 months.
I've read the Baby Bargains review about it not being safe, but IMO it's no different than letting a baby sleep in the Fisher Price RNP - that has a bigger recline than the napper and it also has padding like the napper. And plenty of moms use those. (BTW, does anybody know if Baby Bargains has reviewed the RNP yet? I'm really curious if they have the same "not safe" review as they did with the napper.)
For us, the napper was a nice option because we didn't have the extra bouncy seat and we didn't have the RNP. If you are getting one or both of those, I'd say you probably don't need the napper option.