Sparrow is faster, doesn't take up the same memory that a tab does, and it's faster to find the icon in your Dock than dig through 40 tabs, plus it's nice to be able to quickly switch between Gmail/Google Apps accounts.
I used to use this with Gmail, but switched to Sparrow a few days ago. I've been interacting with my email in a much faster and more fluid way since, which wasn't possible using Gmail/Fluid.
I use fewer site-specific browsers than I otherwise would because of memory usage, but these days many of us have 4-8 GB RAM and running one or two SSBs doesn't break the bank, so to speak.
Chrome's notification boxes have three major complaints from me:
A. They don't automatically close. (I think you can change this for each web app individually, but I would like a browser-wise setting). This wouldn't be a big issue, if not for...
B. The close button is freaking tiny. I can dismiss Growl notifications by clicking anywhere on them, which is much nicer on a laptop than trying to move to a small button.
C. The notifcation windows resemble what Apple calls panels. [1] The problem is, "Panels float above other windows and provide tools or controls that users can work with while documents are open." [2] The user isn't meant to be closing panels often, which is why the title bar can be small. Chrome's notifications feel out of place in that regard.
Is the conversation view fixed in the final release or do they still have the stupid thread view without my sent messages every other client but Gmail has?