SonyAlphaBlog tested the Zenitar 50mm f/0.95 FE lens and concluded:

The Zenitar 50mm F0.95 lens (800 euros) is a massive beast in term of size and weight compared to the Mitakon 50mm F0.95 – Dark Knight (800 euros)
The build quality is lower than the Mitakon with some unusual dampening for the aperture ring and only printed numbers and not engraved. Ergonomically its unusual large diameter makes it difficult to hold the body as there is no place for your finger and the lens hood is moving frequently
The image quality is ok in the centre but the lens suffer from very strong field curvature , very bad resistance to flare, very strong vignetting even with aperture closed down. The very long min focusing distance is also an issue as not allowing very big bokeh balls
Where it shines is in term of color rendition (better than Mitakon) , smoothness of background blur below F2.8 and special soap bubble bokeh at F0.95
If you want a pure 50mm F0.95 that is at ease in most situations: the Mitakon 50mm F0.95 – Dark Knight (800 euros) is a bit sharper on the entire field (much less field curvature), much smaller and lighter with a better build quality , better resistance to flare but with a less nice color rendition
If you want an artistic lens maximising blur (<F2.8) and special soap bubble bokeh with very nice color rendition then the Zenitar will be the one to go
The 7 Artisans 50mm F1.05 (486$) is also a very interesting budget option to try a F1 lens