Both are cool browsers.
I haven't run them long enough yet but the first impression is good.
Palemoon is obviosly more finished but fast and sleek, responsive. I like the interface and the way it loads pages real smooth. I can't yet say if it's faster than Seamonkey but I like what I saw so far.
Xombrero it's even more interesting, a nice blend of minimal browser with more power and potential. As for Dillo, I wonder why it is no longer developed because it offer a good mix of functionality and speed.
I'm still studying the docs I found on the web and figuring out commands and configuration, it will take some practicing.
However I'm writing this post from xombrero while chatting on FB and checking my mail and evrything runs fine.
It crashed a couple times at first, probably my mistake but now its running just fine and, as a laptop user, I like the keyboard functionality.
Thanks for the suggestion, as always very good tip.