When downloading, is 30 KB/sec slow?
The short answer is no, not really.
The longer answer is that it depends. For general day-to-day use i'd have thought that it's quite reasonable. If you're regularly trying to download large files, then it might be a bit slow.
<old git mode>
first modem I had downloaded at 300 baud - that's 0.0375 KB/S, or roughly 1/1000th of what you're getting.
</old git>