For the past few weeks I've been using the Yahoo! Mail Beta but I've decided to go back to the "regular" web accessed Yahoo! Mail interface. Here's why.
I've enjoyed the Beta but I've decided to go back to regular edition for the time being. I have a paid Yahoo! email account and use a Verizon DSL connection accessed via wireless and/or ethernet from a Windows XP laptop, an old Windows 2000 laptop, and an iMac. I've always been impressed by the effectiveness of the Yahoo! spam filters, which is one of the reasons I decided to invest in a paid account in the first place.
The Beta is too sluggish for me. It seems to interfere with what's going on in other "tabs" of my Firefox browser. By "interfere" I mean that it seems that when I'm downloading and building the initial Mail screen other processes behind other tabs are occasionally slowed down as well. This happens on both my "fast" and "slow" machines.
My guess is that there's just too much going on right now on my local machined to manage all the functionality and the sophisticated Outlook-like Yahoo! Beta interface, and this is causing a real local slow down. I push my email and my machines pretty hard and the Mail Beta is just dragging too much. I wish the team luck but for now I have to get some work done...