As to Slimboat, I use Boat here, wondered if they were related. I think it used to be Slimbrowser and was just changed to Slimboat. I have Iron rather than Chrome, and I've removed both Bing and Google as search engines. I use Start Page, Ixquick and Duck. I haven't updated FX on Ubuntu as I don't like the newer versions, and was trying to get ESR. TMobile informed me my browser was out of date. I update most of the other stuff, I just uncheck FX and Mozilla. I haven't used it for a while, anyway.
SlimBoat and Boat have no relation at all, apart from they're both Webkit based AFAIK. SlimBoat is American, Boat is not American..sure the name comes from Beijing Office Automation Tech, or something like that. SlimBrowser is really IE with a different interface, it uses IE's Trident engine.
The only thing FX has going is tab permissions. I don't have to look at a page full of images if I don't want to. I can turn them off on the fly. The new Australis is going to look like Chrome, and I'd rather have the menu bars where I can see them. Pale Moon (based on Mozilla) doesn't do Linux or Mac.
BTW, you have to edit a lot of crap in About:config. Mozilla has hooked into some social sites, and if you don't like it, you edit it. I want a browser that does nothing but browse, if I want a link, I bookmark, I can use tabs or not and all the toolbars are available. I don't like the damn speed dials either. They take up too much real estate. I can read faster than I can recognize the icon and a line of text is faster.
I'm sure both SlimBoat(Ebay and Amazon affiliate) and Boat(ad-ware) are heavily hooked into some affiliate and ad stuff. Monetisation in return for giving you nice "free" browsers. So something to be aware of if privacy and tracking are of a concern to you. Plus Boat is almost certainly phoning home to Beijing as well. In the same manner that Dolphin does, also Chinese.