Well, I don't think you really need to go into detail about which one the OP wants. It really is simple, he wants something simple, just the basics and by the sounds of things something easy to use and that is without a doubt chrome....
And before people shout GOOGLE FANBOY from the rooftops, I mainly use firefox
Firefox:
+ Much better page rendering than chrome, renders the page as whole as opposed to rendering whilst loading the data on chrome, so the page isn't render as a "whole"
+ Without a doubt, much better addon system, and a lot more user styles actually work properly on FF
+ A heck of a lot smoother when scrolling especially in the high res screenshot thread
+ loads image intensive etc. pages much quicker than what chrome does
+ Fully customizable
+ Uses a lot less RAM for me (yet I have loads more addons, user styles installed on FF than chrome)
+ Text is easier to read and looks smoother
+ Remembers where I left off on web pages, so means I don't have to scroll all the way down looking for the last post that I read
+ much better for bookmarks, can add separators, which is essential if you have loads of bookmarks and like to keep thing tidy and organized
- Overall UI isn't as smooth as chrome and from time to time has the occasional lag
Chrome:
+ Neater/tidier UI for the options/tools/extensions and overall IMO a slightly better UI than FF (you can get a theme that looks just like chrome for FF though)
+ Faster at loading just text based pages, like this thread
+ Better built in download manager and integrates into the same window (although there is an addon for firefox that does the same and is more customizable)
+ Chrome gets some google features and experimental stuff first, which other browsers don't get
- Not smooth at all when scrolling (even with GPU stuff enabled in about:flags) especially in the high res screenshots thread
- can't customize the look at all really apart from themes that just change the colouring
- Doesn't remember where you left of when reading a post on threads etc. once chrome is closed and relaunched again, it reloads the page and puts you back at the top
- will show the stock look of a web page first and then switch to the user style installed quickly e.g. for this forum, if you have a black theme installed, when loading a new thread etc. the blue old look will show for a split second then switch to the black style, rather annoying that
Probably some stuff I missed, but that is from my usage with both regularly, I used chrome for the last few days as I really want it to be my main browser again but all the negatives are just too annoying for me and the firefox positives by far outweigh the positives of chrome for me!