I have been testing, and I like it so far.
Pros: Speed is there. The excel add-in is native excel, and much more useful than the designer from before. It reminds me a lot of FR from Accpac, except that you don't have to re-run the report every time you change the formula to update the numbers. It's all Excel. There will be very little training for someone who understands Excel. I'm guessing you'll start to see some really eye-popping financial statements.
Cons: The built-in lists leave a lot to be desired. I'd like to be able to have both the account, and the group, and the account type. They say that this is coming soon, but we'll see. The functions don't take into account that a balance sheet account is a snapshot and an income statement account is a measure of activity. I'd like to see the balance sheet account balance, and not have to do two formulas to figure that out.
I'm happy to answer specific questions if there are any, so bring them on.