TumblTwo has several improvements over TumblOne, featuring:
- multiple simultaneous downloads
- download queue
- multiple selection (add and remove multiple blogs to queue)
- setting to change download location
- setting to turn picture preview off/on
- setting to define number of simultaneous downloads
- set imagesize of downloaded pictures
- a 'Date added' column
- displays if/when the blog was last crawled
- saves and restores settings
- resizable UI
You can grab your free copy of TumblrTwo for Windows here.
Mac OS X users: your best bet is still the Downloader for Tumblr app.