You’re going to find the same network speeds (the only thing that changes is the amount of data allocated per-droplet, per month before incurring an overage when bandwidth charges go into effect) on all of DigitalOcean’s droplets (these are virtualized compute instances; not dedicated hardware). I recommend, if you’re concerned about network performance to and from a specific site from your DigitalOcean droplet, that you test the regions using DO’s speedtest sites:

http://speedtest-sfo1.digitalocean.com