If you're after shared seedboxes, give http://mybox.pfcorner.eu/ a shot. I've used them extensively in the past with no issues at all. IMO their plans are the most cost effective ones out there.
They seem to have some sort of auto-restart feature as I've never seen my seedbox down for more than a minute or two. Speeds are consistent but not the fastest, as I recall up to 2MBytes/sec on their smallest plan.
If you want a server instead, filesharingtalk seems to go largely with OVH servers *cough* but do check out their discussion threads on using their servers as seedboxes before you order one.
The seedbox itself isn't so much of a problem as US providers concern for US piracy laws (even though you having a seedbox doesn't necessarily mean you're doing any piracy at all and there are plenty of legal uses for this). If you're not breaking any US laws and only torrent legal content by those standards, I would think that most US-based providers would work just fine as well (or in any country relative to the local laws). Some may simply have reservations due to the problems that seedboxes can tend to attract.
Corey Northcutt | Northcutt Competitive inbound marketing with a hosting industry competency. Social | Content | Optimization | Outreach