We've had DD in one from day 1 and she loves it. Sleeps in it day and night. I'm now trying to transition her from that to the cot to get her used to the cot too so that one day when she sleeps full time in the cot she'll be used to it.

The hammock is great because you can bounce them off to sleep if they stir without getting them out again and picking them up iykwim. It's in our room next to our bed and you can see her easily.

Well worth the $$ I think. Although some babies I've heard just don't like them so it's one of those things you'll just have to try.