Sure, sometimes text-only zoom breaks the layout, but usually only if you zoom in a very large amount, and often times, it is still preferable and easier to work with.
I surf the web with my text zoomed in 4-6x.
For me, Chrome has nothing Firefox don't have. Both have almost same set of features now . A year back, Chrome was in fact lagging in features. IMHO, the only difference i find is startup speed is better in chrome. But Firefox 4 nightly builds are rapidly catching up in that area. Load times for me are 5-10 seconds with a big Adblock list pre loading. Without Adblock list, it's a snap.
Both are rapidly catching up with each others features and so I don't find reason for me to switch to Chrome.
Firefox + Sync + Adblock + No Script + Awesome Bar is virtually unbeatable for me even though Chrome has equivalents.
(edit: and option -> an option)
I empathize.
I'm a bookmark junkie, keeping 10,000+ bookmarks in my browser at a given time. Firefox just couldn't handle that (on my admittedly older computer,) taking ~30 seconds to both start up and shut down, and ~5 seconds to navigate to a new URL.
I blame it largely on the switch to SQLite as backing store, but unfortunately I don't have any hard numbers.
Del.icio.us responds at the same rate, whether you have 10 bookmarks or 10 thousand.
I think FF4 may get me to switch back as there are a few extensions I miss, oh, and the in page search sucks compared to firefox. Nothing like pressing / to search, maybe I should install Vimium.