Doppler

Which doppler would you recommend buying that is good at finding the heartbeat at the early stages of pregnancy?

My sister is letting me use her Sonoline B and I'm 9 weeks and was able to find it!  

I have the sonoline B 3mhz.

Does this mean something good??

I have an Angel Sounds and have been able to find the heartbeat for about 2 1/2 weeks now(I've only had it that long).

I have the sonoline B and I bought it on ebay for around $60 after shipping. I've heard pretty much only bad things about the cheaper ones that you use with headphones.

Sonoline B!

For who?  

I have the sonoline B.