Well, one poster put a brief comment about the 6700 on this thread, which I find ironic since the literature I've seen on the x700 models seems to show that they are all square heads. The English catalogue on the Japanese site doesn't have the 6700, though. The Japanese catalogue doesn't have any of these new x700 models. Gosen America and Gosen Denmark don't have anything more current than the 3600. At least the Japanese catalogue has the 6000 and all the R2X ones.
I have a 6700. I'm quite satisfied with it, because I feel that its has the right weight and right balance for me, and it has improved my game greatly. However, I've not tried that many rackets and therefore, cannot give a good comparison with other rackets. My advice is to keep an open mind, especially if you're looking for something other than Yonex, and put a 6700 in your hand and try it out.
I guess the 6700 looks like an almost oval head. The 5700 looks like the most square. The 3600 and the 2400, which I have, are slightly less square but the 6700 is almost completely oval except for a tiny flattish part at the end. I still have yet to see a 6700 on a Gosen site.
