Upstore is good, here are my plus and minus with their service:
Good:
Always pays on time, automated.
Easy to use site and friendly interface.
Staff replies to your questions.
Good uptime.
No shaving as far as i can tell.
Bad:
Their ftp server system is terrible, you have to manually check which out of their 100 + ftp servers have space free and then upload to that server, next time that server may be full so then you have to check again for another server to upload to, this is annoying as hell if you're an expert uploader and do this a lot.
After uploading files every 1 file out of 40 gets lost in cyberspace, this was essentially the issue that made me stop using upstore, i have huge collections of files and rar archives that stick together, lots of times random files are missing and the amount of overhead to find those files and fix them manually was to much work for me.
Hope this helps.