Eh, once again it depends. No doubt, Leopard Webkit is notably quicker, but I also find it to be a lot less stable. On really heavy pages, sometimes it will randomly crash, and when it does, I cannot use it again without restarting my Mac.
On the other hand, with turning off extraneous scripts in uMatrix, TFF picks up speed, and while not as quick as LWK, it is much more stable, more secure, and more standards compliant.
I find that in PPC, I use a complement of browsers for various tasks moreso than just one browser for everything. (In addition to LWK and TFF, I use TenFiveTube regularly for watching Youtube).