I solve the cross on the bottom, and I find it helpful. I have no problem doing it on the bottom, and it's not really taht hard. If you turn the cube upside down, you have to look for about 2 seconds for your first F2L pair, corner, and if you want to be really fast, 2 seconds can be time consuming. Doing the cross on the bottom also allows more U face turns, and gives you a better view of all the cross edge pieces.
I do the cross on bottom.
I saw one vid of Erik though (IIRC), where he did the 3 cross edge pieces on top, and had one cross edge piece on the bottom, then a single r2, and bam! instant bottom cross.
Top assembled cross instantly went to the bottom without any awkward x2 or z2 rotations.
Cool, I thought I was freak doing the cross on top and then flipping!!! I have tried to do it on the bottom but I just can't seem to see it nearly as well as on the top. I was feeling really guilty for not switching to the bottom but now I can rest easy that I am not alone
I do the cross on bottom.
I saw one vid of Erik though (IIRC), where he did the 3 cross edge pieces on top, and had one cross edge piece on the bottom, then a single r2, and bam! instant bottom cross.
Top assembled cross instantly went to the bottom without any awkward x2 or z2 rotations.
Interesting.....I am gonna try this. I have always rotated the whole cube but this could be faster when taking into account the single peice on the bottom was probably put there very easily during one of the other insertions.