I have been using Oppo Enco M31 for almost one and half years now. I have been using Oppo Enco W11, M31, W51, Sony WF-1000XM3, Audio Technica ATH M20X, and AKG K361BT on various devices and places. The only reason for me to buy another earphone was that the right side earbud of my W51 stops working intermittently and gives random high pitch noise. And they do not repair/ replace it as it is out of warranty.
First thing which you will notice about M32 is that the size of the neckband is big. Much bigger than the M31. Probably that is the reason they are offering 28 hours of battery life. Earbuds are round and come out of the ears compared to M31, which is oval and part of the earbud is on the ear space. So if you like using your earphones while lying down on sides, the M32 design is a discomfort.
One of the major features missing from M32 is LDAC codec support from M31. It is a major downer and people looking at the good sound quality of M31 should stay away from this one. Bluetooth pairing was smooth and there was no connection drop during my testing.
The most prominent thing about the sound from Oppo Enco M32 is bass. It is so prominent and overpowering that it masks everything else. I could not hear the mids and highs properly in most songs due to the boomy bass. I think these earphones are one of the worst branded earphones I have heard in a long time.
M31 had such a nice and almost flat sound signature, which, when combined with LDAC, gave excellent sound quality.
I got Oppo Enco M32 for Rs. 1500. I think it was a total waste of money. Only buy M32 if you want good battery life. If you want good sound quality, just stay away from these.