I agree our ability to scale support is a problem. Very sorry it didn't work out for you. Unfortunately on our side it's a big challenge to provide detailed troubleshooting with individual users, especially if they are not paying. We took Patio11's advise and offer a money back guarantee for paid users, but we also do try to investigate and support them much better.
Since the product is zero knowledge, we can't just look at the server to see what a problem might be. Trobleshooting involves analyzing logs from the end point devices, find out all the relationships involved in the sync (one machine is Mac using case preserving insensitive unicode form D, the next is Windows with relevant regional settings, another is a Linux NFS server, a FAT32 volume that doesn't preserve certain characteristics and has a limitations for MAXPATH, etc.)
It often take a couple of hours of analysis to understand what a specific situation's problem might be, and the median case is that it comes down application level things that SpiderOak can't do much about other than explain to people why syncing (for example) Quickbooks files between two open and running instances of Quickbooks at the same time is not going have the effect they desire. Or any number of combinations like that. People put very weird stuff in filesystems.
In any case, sorry it didn't work for you. We did recently finally resolve a couple of long standing edge cases in the Unicode sync logic in the 5.0.3 release. Let me know if you'd like to give it another try. In any case, thanks for your interest in SpiderOak.