SpiderOak is well suited for local backups of the computer the client resides on. It is well suited for local area storage backups. It is less suited for remote backups, over a VPN or wide area where the data is continually changing. For data that continually changes, like in our document management system, the client needs to be on the same network as the data.
I would definitely recommend WeTransfer - especially the paid version. I feel like all of the shortcomings with the free service (file size limit & content deletion after 7 days) are all fixed when you upgrade your account, and the service is not very expensive. It only costs $12/monthly or $120/annually. WeTransfer makes it so easy to send files, and the additional features such as creating a link to your content & password protection are great. Very straightforward & easy to use.
WeTransfer is extremely reliable 99% of the time. There has been twice in 4 years that their service was unavailable due to server outage for several hours.
While I gave them a 7, it is in regards to the access to support. This is a business application and not being able to call them can sometimes be a problem especially when you need immediate support. They still tend to manage their support on a consumer line model and not a business grade model. With that said, I will say they are very knowledgeable of the product and how to resolve most any issue when I contact them.
I've only reached out to WeTransfer support once, but they were prompt, courteous, and answered my question. I assume that future interactions would be the same, I'm looking forward to being a long term customer.
In regards to overall performance SpiderOak is not as customizable as Unitrends, but based on the annual cost for SpiderOak and how we use the product, for a "Backup" to our primary backup solution, it is a welcomed option to our backup strategy when you consider the versioning, zero knowledge, share features and unlimited data.
I did not choose to use Image Relay, the client did. I really like Image Relay and the fact that you can organize files in different folders, but not the fact that you have to create an account, have access to all the files and folders, and remind passwords. With WeTransfer skipping all these requirements, it is way easier and faster.