It's definetly nice to have a piece of mind. I first heard baby at 8 weeks an I still use it even though I can feel her move.
The only down fall is when you can't find the heart beat most moms panick an go to hospital thinking something is wrong when baby is probably hiding, so it's best to put it away and try again later. :)
I don't remember. Its packed away. Angel something. I bought it from eBay for 22 dollars.
I have one. I got it to use during the first trimester. I dont use it now since I can feel baby move :)