The two headphones you are deciding between are two very different animals and really made for different purposes. The Bose are wireless, noise cancelling, microphone, closed back. The Sennheiser are wired, open back. These are all major differences. So it really depends on what you want to use them for.
Since you have Sony MDRs, have you heard an open back headphone like the Sennheiser HD660? They are a bit different: you will be able to hear external sounds, and you people close to you may be able to hear your music if played loudly. So that is decision #1.
Decision #2 is whether you need noise cancelling.
Decision #3 is how good the wireless Bose sound with whatever music you listen to vs. the Sennheiser.
With regard to #3, I can tell you with a good bit of confidence that the Sennheiser will sound much better than the Bose if you are sitting in a controlled environment. I have a pair of the Sennheiser 58xx (Massdrop) and a pair of Sony WH-1000XM3. The WH-1000XM3 are fantastic for air travel, which is their intended use (noise cancelling). But they are not in the same ballpark with the Sennheiser in sound quality when using them in a quiet place. I also have some wired Sony MDRs and again the WH-1000XM3 are way behind.
So I would say if you are planning to sit at your desk and listen to music through a headpone amp, consider the Sennheiser - or some other wired passive headphones, like those mentioned by ShiZo. There are plenty of reviews for the Sennheisers, because they are widely considered a great sounding headphone at the price and almost a defacto benchmark for at-your-desk listening. The Bose will only be the better choice if noise cancelling or wireless are important to you; and if they are, that is OK, too.