I'm a fan of the flexibility of tablixes (tablices?) but one thing I find really awkward/annoying about them is when saving as XLS, you inevitably end up with merged cells or worse, weird anomalous rows and columns if you have any media / images in the headers (usually down to alignment of edges of things). The resultant output is pretty user-unfriendly...

Worth noting, to anyone starting out with them. If you have users that like to autofilter xls outputted reports, you may wish to look elsewhere.