My original AppleScript, which I have been running on my HTPC Mini for ages, supports drag-and-dropping any number of input media files. This feature is still supported in the Techila-powered system. Technically, the only change which I did to the original script was replacing the direct FFMPEG call with a wrapper function call, which splits the media file(s), launches the original FFMPEG call on the computers in my system, and joins the processed media files.
I have not tried this with MPEG Streamclip. Basically, I do not see any reason why you could not use this with MPEG Streamclip. MPEG Streamclip would be good at least if you have a only Macs in your environment, and if you have a folder full of media files, which you just want to get encoded. My solution can speed up encoding a folder full of files and individual media files.
Openly, I am not very experienced with the Streamclip and all its options, since I have done my projects mainly using EyeTV or FinalCut and FFMPEG. FFMPEG looks a bit lighter than MPEG Streamclip, which is an advantage on the first launch of the distributed processing (as Techila distributes the required libraries automatically to the Workers). But that is a one-time cost and the difference is probably not more than a couple of seconds.
At the moment, FFMPEG is my preference because it I know its options and it is cross-platform, which allows me to include Linux and Windows instances to support the encoding if I want to.
FFMPEG uses libavcodec, which implements a nice number of codecs. The list of formats supported by libavcodec are listed here: http://en.wikipedia.org/wiki/Libavcodec.