I also had the Spatial M5 Sapphire for a few weeks and couldn’t stand them. They had none of the magic that the Vandy’s have. AND the speakers were damaged in shipping returning them to Spatial and Clayton put me on the hook for the costs. If it wasn't for the buyer protections on my Citibank credit card I would have been out the $2300 or whatever the costs were. Buyer beware.....
Strange. I had quite the opposite experience with Clayton and Spatial. While I ultimately didn't keep the speakers due to room constraints I had at the time, the transactions were smooth and painless.
To the OP,
Having owned the Spatial M4 Turbos and M4 Triode Masters, Magnepan 1.7is and .7s, Vandy 2Ce Sig IIs and 1Cis, my bet is the M5 Sapphires would be the best performance value in your space. Of all the speakers I listed, the Vandy 2CE sigs were the most disappointing. I couldn't get them to sound good and my 44-year- old Large Advents outperformed them in many regards. I still own the .7s which I prefer to the 1.7is. The .7s have a rare and addictive musicality but are not as dynamic as Spatials and obviously less efficient.
If the M5 Sapphires are indeed an improvement over the M4 Triode Masters, they'll outperform most of the aforementioned speakers in three main respects: bass texture, detail, and high frequency distortion. The 2CE Sigs don't hold a candle in those areas. The Maggies can manage much of the bass texture but lack the resolution of the Spatials.