As someone with both tools (and the complete set of both), I can offer a few words and opinions.
I think the ADDT suite was easier out of the box, but I feel the WebAssist products allow me to do much much more as the code is far easier to modify/enhance/add to. But I do several complex projects that require me to do a great deal of hand coding, so ADDT - at times - was not nearly as flexible.
I have found WA to be able to do everything that ADDT could do and more with two exceptions. One is the "reorder" that you mention. While, yes, you could create an order-weight column and modify a few things, it's not as easy as ADDT's AJAX order arrows were where you could move things up and down and then click "save" on the top of the column to have the database save the new order.
I, however, have begun playing with a few AJAX scripts to see if I can modify it myself to easily be able to add that functionality to data tables created using WA's DataAssist. Of course, I will post it here if I get the time to complete it.
The other thing I thought ADDT was very good at was the Multiple Image Uploader that invoked the flash object to quickly upload and resize up to 200+ photos really quick. I found this to be great when creating photo galleries. The good news is that ADDT multiple image uploader still works OK on the latest PHP servers that I am using, so I use it in conjunction with DataAssist when creating photo galleries.
In fact, I still use several ADDT behaviors (such as "show if condition is met", etc.) alongside WebAssist with no problem at all. But I would recommend staying away from ADDT behaviors that require several includes and email transactions as I have found that much of the code used in those "heavier" behaviors fails in PHP 5.2.10 and up (such as user registration with email confirmation).
The last thing that I really like about WebAssist is the user community is far larger here than that of ADDT. And even better, when you have an issue here, the WA staff will actually respond to you on these boards to help you with solutions (something Adobe never did with ADDT).
Even better is the fact that the WA staff is reading these forums and taking notes and using information based on user needs to add functionality to their existing products and to create and release new products.