I had a harvey and hated it - sold the ungainly thing to buy a Littman. Agreed that it's clearly louder. As a resident I really think that loudness is going to be the most important thing for you, so I'd recommend a Littman. Maybe the Harvey is more precise for cards fellows or attendings, but in my experience the kiddos with Harveys struggled to hear anything at all so the precision never mattered. Littman's also look better to me, but that's obviously just personal preference.
All those fancy bells and whistles aren't necessary unless you're doing cards. My stethoscope has never been the limiting factor in diagnosing a murmur - it has always been knowledge and experience and will almost certainly continue to be so. End of the day, stethoscopes are like golf clubs. I'm not shooting in the 90s because my clubs suck (they do) - I'm shooting in the 90s because I'm not good at golf. Get whichever one you like better and use it constantly - listen closely to every patient you admit, try hard to ID the murmur, etc.
