Unfortunately the OP has not declared which country they are in or whether either brand is readily available from an authorised distributor, in our case which I have pointed out previously this was a major factor in deciding on a particular brand. I almost got the impression that owners of the SDM-3055 had in some manner committed to a non disclosure agreement under the conditions of purchase, really just bugger all feed back from end users other than "I'm happy with it".
At this point in time there is no full review or video, no disclosed pending or addressed bug list, even Siglent have failed to promote the product by means of a video which nowadays seems to be an accepted method for valid products. This meter on paper ticked all the boxes for our needs but sadly it was the stuff that was not documented or disclosed that steered us in another direction.
And I would like to add if I may a big bundle of gratitude and thanks to tautech for his patience, efforts and understanding with our enquiry into the product.
Muttley