I have a Welch Allyn DLX, a master cardiology, Littmann cardiology IV. Used to have a Littmann cardiology III before it walked away.
The cardiology IV has the best diaphragm. the DLX the best bell. Personally the master cardiology is mediocre and often I can't get purchase on a bony old woman or a COPD'er with it.
For everyday use either a DLX or Cardiology IV. There is a reason most people use the littmann cardiology III or IV.