If the M2 only sound "slightly" better than the QC35 then Bose has made great strides since the QC25. The M2 is a full, rich and detailed sound compared to the QC25. As far as price, I paid the same price as the QC35 for my over ear M2 wireless. Size wise, the M2 over ear are very portable and comfortable. From what I remember, comfort and noise cancellation were the strong suits of the Bose. Sound quality was middle of the pack. Again, if the QC35 are greatly improved, and I am not referring to inflated bass only, I will have to try them.