I've used an iPad Mini on my last few tours and it's worked well for blogging purposes (ingesting and editing photos, uploading posts to my Wordpress-based site). The Mini can also be used on Verizon's network, so I don't have to rely on a wifi connection. I only activate this feature during tours.

Using the touchscreen keyboard isn't ideal. There are keyboard attachments you can use via Bluetooth.

The Mini is a good size. It's big enough for photo editing and small and slim enough to fit in a standard handlebar bag or, in my case, a Revelate Pocket.

Another benefit of the Mini, or any tablet for that matter, is that you can charge them with a dynamo hub. I prefer to be as independent as possible when traveling. Hunting for outlets to charge my devices isn't appealing.