Larger test files on the speedtest servers (e.g. speedtest-lon1.digitalocean.com) would be useful.
Currently all location test servers only offer 100 MB and 10 MB test files, whereas 1 GB and 10 GB - even 50 GB - test files are increasingly useful as superfast home and business connections become ubiquitous.
While the speed test applet runs multi-threaded tests, it is equally useful to measure the single-threaded performance of your connectivity to DigitalOcean as this highlights any problems with intermediate transit providers or the connection provider.
For example, on my home connection, I can download the 100 MB file in about two seconds, which isn't very helpful when trying to measure steady throughput over a minute.