Ok so i was just like you i was that close to buying one as well, UNTIL

someone said to me what happens if you buy one and you can hear your babies heart beat oh so nice. then the next day you wake up and and the bubs has moved and you cant find the heart beat you are going to stress out run to the hospital or doctor only for them to tell you oh bubs has moved bubs is fine heart beat is just over here now!!!!
Also i think dont quote me but arent they bad for bubs if you use them too much?? I know that you won't use it too much but just be careful

So i did not buy one!!!

Good luck with your decision