I hope this could help you to choose. Try to refer to these links:
http://lifehacker.com/the-best-cloud-storage-services-that-protect-your-priva-729639300
http://www.pcmag.com/article2/0,2817,2413556,00.asp
http://www.pcadvisor.co.uk/test-centre/internet/14-best-cloud-storage-services-2016-uk-copy-3614269/
http://www.cloudwards.net/top-10-secure-dropbox-alternatives/

I'm using dropbox, have you tried it?