I have been using The Seedbox Company for three months now and I'm very pleased with them!
From the first day of the service, customer service was highly attentive and replied to any request or feedback I had about the seedbox service. I even encountered some issues that were so rapidly fixed I was quite impressed with the fast response.
I have the SB-50 package that offers 1 Gbps download an 50 Mbps upload, and I've managed to reach the 125 MB/s download speed quite a few times on healthy seeded and size-heavy torrents, so I can honestly say that the speed they offer, is the speed they provide. The same can be said with the upload speed, it's quite good .
The HDD space they offer with the plan I got is 740GB, and it truly is so. They don't take away any space if you install apps (they offer: RealVNC, ZNC, RapidLeech Server, Resilio BTSync, Madsonic, Subsonic, Plex Media Server, irssi and mktorrent web UI).
You can choose from 3 torrent managers such as Deluge, uTorrent and Transmission. I tried them all, and am sticking with Deluge at the moment.
I also think the service/cost relation is quite good in my opinion. I've tried two other providers in the past and I was not happy with them, because they were lacking of a good customer service or they offered something different than they actually provided. I'm glad to say I haven't had any of those issues with The Seedbox Company, so I highly recommend them to you!

- J.P.