I don't know if other people are experiencing this, but the program slows and slows the longer it's open until it bogs the whole system down to being nearly unusable. Restarting the program fixes it. I should probably say that the problem seems to correlate most directly with how many other users shares I browse, more than how long the program's been open.
Watching Activity Monitor, I've concluded the slow down comes from some RAM problem, possibly a RAM leak, or maybe coding something so that it uses recursive rather than iterative algorithms when working with the XML files ofr other user's shares. At any rate, when I launch the program, it uses under 100 MB of RAM and about 100 MB of virtual RAM. After having it open for several hours, it's now using, between Shakespeare itself and its spawned processes (sphubd & sphashd) 700 MB of real RAM and another 1.5 GB of virtual memory. The slow downs, I'm pretty sure, are due to RAM cache swaps. The processors hardly get used at all, but the disk drive and RAM go nuts. This slows the machine down more than running any other 10 I/O intensive apps at once; I've never seen anything bog down my G5 like this does.
Otherwise, it's very well laid out, and user friendly. Nice program. I guess my only other complaint is that I sometimes end up disconnected from a hub without the program telling me, which is annoying.