One thing I've wanted to do is access files remotely without downloading them (streaming/virtual drives, etc). Do any of these services allow that (BTsync, dropbox, aeroFS), or am I forced to download files before accessing them?
Can you discuss how you may be better then they are? I am actually a bit unhappy with them, as I occasionally have strange behavior where a file refuses to upload, or the cache sometimes quits updating. However, my version is a few years old, so perhaps they fixed these issues. I have thought of buying their new version, but I am open to hearing why I should switch.
I think it is an all around better product. No need to tweak settings to make it work. It's generally faster, licenses are cross platform, we support more protocols. It's less expensive. We care :)
Checkout Bitcasa [https://www.bitcasa.com/]. If I understand you correctly it does what you want. Their website is frustratingly scarce on technical details but I've tried it and it works as they describe it.