As far as biomechanics go tibia>femur, And IMO it looks much better.
Here is some info i found.
Just recently there was this debate on a health and fitness forum about barbell squats. In particular, femur length and squats. The actual issue was the ratio of the lengths of the tibia and femur and whether this made squatting difficult for people who have relatively long femurs. (Of course, the concept of “relatively long” was missed, and replies like “I know this guy who’s 6’5″ and he can do ass to grass squats without any difficulty, so everyone else is just making excuses” followed. So it had to be pointed out that the same problem can be expressed in terms of having a relatively short tibia compared to the femur.) I have known since university that neanderthals had a relatively long femur compared to the length of the tibia, but it’s hard to tell and journal articles post ratios of actual bone lengths and you can’t very easily measure your own bones while you are still alive.
In any case, it made me do some research and I found amongst other things this article and apparently yes, having a relatively long femur compared to you tibia does indeed give you a significant mechanical disadvantage for squatting in a normal stance. This is rectified by taking a wider stance, so that the torso (and center of gravity) goes between the feet, rather than trying to keep your center of gravity over the feet, which is not physically possible if you have a short shin plus a long femur, because your center of gravity is further back and you either fall backwards, or you have to lean so far forward to stay balanced when your legs are horizontal to the ground, that a) you can’t physically get any lower because your torso and quadriceps can’t occupy the same space at the same time and b) if you try that with a barbell on your back you’ll do your lower back in.