Recently, I picked up a copy of TinyGrab from the current MacHeist Nano Bundle. After playing with it for a few days, it has given me some suggestions for improvements to my screen capture app of choice, Skitch. While TinyGrab is very useful, giving the ability to take a screenshot, automatically upload the grab, and copy the upload URL to your clipboard, it still lacks a lot of features that I use on a near-daily basis. For example, with Skitch I am able to apply notes and markup to an image using the built-in drawing and type features. From here, I have multiple choices of where to upload the file: Skitch.com, MobileMe, FTP, SFTP, WebDAV, and Flickr. Also, I can drag my marked up image into an app that supports drag and drop (e.g. Mail.app), or straight to the desktop to create a file for later use. Skitch even gives me the ability to save images into a history, letting me recall past images without having to save them in another location (although, it does create a new folder under your ~/Pictures directory). TinyGrab does gives me the option to also save the screenshot to the desktop, but I'm pretty limited in my web-export choices.
Of course, the main benefit from TinyGrab is to make sharing screenshots easier, which it does quite well. I would love to see this functionality in Skitch; I have even submitted a feature request for it. Having the ability to automatically upload a marked up photo, copying the image URL, and being able to paste that into a chat window would remove a few steps from my current workflow (having to manually go to the upload web site and copy the URL). There have been times where I was prototyping logos and this feature would have saved an immense amount of time.
TinyGrab, on its own, is a great app for people that need to share screenshots on the fly. However, for the power user that needs more from their screenshot app, my personal recommendation is still Skitch.