I have 3 shaves under my belt with the Rocnel GEM SE. Here's just a broad brush comparison with the vintage GEMs. This is not a one-to-one comparison of any individual vintage GEM vs this new razor. My experience with the Vintage is that I have shaved with 1912s, 1912 Juniors, Damaskeenes, G-Bars, Contours, the pushbutton. I am not an expert with vintage GEMs. But I do have some familiarity with many. As for the final result, I get the same high-quality shaves from the new GEM as I do with the vintage GEMS. The main difference for me, is that the razor for the most part feels more sturdy, more substantial, like the razor itself is adding to the rigidity to the already rigid GEM blade; giving me confidence to attack heavy growth without tugging, which sometimes happens with some of my vintage GEMs. Maybe it's technique on my part, but for the 3rd shave in a row, I've had NO tugging, only a sensation of a sturdy tool, cutting through beard growth.
For a large part of my vintage GEM shaving experience, many times I would feel a sense of flex, like maybe the head is moving just a wee bit. Not sure if that is actually happening. But I think the Rocnel's handle is closer to the center of the razor's head than that of most vintage GEMs. So, this reduces the moment arm, or leverage so there might be less tendency for the head to "flex" a bit. Also, there is substantially more material on the Rocnel where the handle goes into the head...like a beefed-up flange. This too adds to the overall stability of this razor.
As for looks...I like it more in person than in the pictures. It has that cool gadgetry kind of look. But, to me that is secondary to how it performs. As noted above, the final result as compared to vintage GEMs, it's equal for the most part, but it's "the getting there" that was more enjoyable for me. Also, for me, I didn't feel like I had to get too worried about "light pressure". After learning it, I just shaved. Carefree, no worries.
Oh, one other comparison to vintage GEMs. I found this razor easier to shave ATG underneath the nose. This is a notoriously difficult part of my shaving, and few razors can perform this smoothly.
Although I like my vintage GEMs, this is my favorite GEM thus far. And not because it's new...I seldom shave with the same razor 2x in a row, let alone 3x. I looked forward to shaving with this guy.
I hope this might help those that are on the fence about getting one or not.