I love my Master Cardiology Special Edition steth, but it was a gift, so I didn't have to pay for it! 🙂 When I worked on an ambulance, I tried many others' before deciding to ask for the coolest looking one. :😀 (horrible, horrible, I know, but the Littmans were all very functional).
Sometimes it can almost be TOO loud, because of all the noises it will pick up (like when you're doing lung sounds and the ambulance drives over gravel in a construction zone, it's VERY odd hearing Michelins vs. gravel THRU the body of your patient!!).
I think you'd be pleased with ANY of the Littmans, maybe other brands too, but I'm not familiar with them. Just make sure to get a tag, AND get the bell engraved with your name. It's easy for someone to mistake yours for their own, and even easier for someone to "borrow" yours... and then it's gone forever. 🙁