Looking for an OS X Tumblr app? myTumblr is a pretty snazzy option
Aside from Tumblr's oft-broken web interface, there are some reasons that you may be looking for a desktop app to handle your tumbling. If that's the case for you, myTumblr is at least worth checking out -- it's free to try, and could be well worth the $14.99 price tag if you're a serious Tumblr user.
myTumblr more or less acts as a direct replacement for the Tumblr Dashboard. It does have some nice perks in addition to that, though: it allows for multiple accounts and fast switching between them all, auto-refresh of the follow-feed, drag and drop for multimedia posts, and built-in FTP.
The drag and drop feature is definitely nice, but to beef it up some basic image-editing options (which might be the biggest feature for many Tumblr users) have been added to the app. You can also simply provide a source URL for an image on the web, and sending your post to Twitter is as easy as a ticking a checkbox.
There were only two things that really bothered me when testing this app. The first is how it displays the regular follow-feed --mainly that it displays images as small thumbnails to the far right. Sure, you can just click them to see the full-sized images, but the regular web-based Tumblr automatically displays all images in nice 500 pixel-wide format. People who mostly follow wordy tumblogs would probably not find this to be so annoying, but given that Tumblr's such a great place for images it seems like a bit of a waste.
My Second and probably biggest gripe is that while MyTumblr has built-in FTP, you can apparently only use it for audio posts. Images and video only have options for upload to Tumblr or providing a source URL. To me, that feels like the entire FTP function is useless unless you're using Tumblr to promote a band.
As I mentioned, registering the app will run you $14.95 (USD) -- enough to make most think twice about ditching the browser tab for a desktop app when in the end, they both accomplish the same thing. Fortunately, there aren't any limitations in the demo, so you can take your sweet time on deciding whether or not you want to register (and presumably keep using it).