I've previously recommended Wuala, but its gotchas are pressing me to look for something else. Wuala was acquired by American company, which makes it no more safe than SpiderOak, for example. Wuala is reportedly using convergent cryptography, which makes it even more questionable as a privacy service.
There are really only three players in the client-encrypted cloud storage: Wuala, Tresorit, and SpiderOak. Mega is nice, but one never knows when is it going to be shut down by the copyright lobby (which is dying but not dead yet). Others either use cheesy crypto assuming I am too stupid to find out or they outright disregard privacy assuming I am completely incapable of comprehending why privacy is needed. There are bolt-on solutions for originally unencrypted services, but their bolt-on wrap-around nature makes them too unreliable and in the end leaky.
Tresorit appears to cost the same as Wuala: 10€ for 100GB space. So far so good. The first gotcha becomes visible while ordering the trial. Tresorit charges VAT separately, which rises the price to 12€. Okay, it's not that big difference. The next problem is sharing.
Tresorit follows DropBox model where shared folders are counted towards quota of all folder members. Wuala follows Google Drive model where only the original uploader of the file pays for storage of that file. This makes Tresorit crazy expensive in family setting. I can upload family photos or even videos to my paid Wuala account and share them with family members who only need the free Wuala account. Tresorit apparently expects me to shell out those 12€ for every family member. Tresorit also doesn't care that it is now difficult to share with extended family. While Tresorit focuses on businesses, I can see how this is going to be a problem for businesses that would like to share files with clients and contractors.
Lastly, Wuala's paid plans start at 3€/mo for 20GB, which is often enough for small-time users. Tresorit's minimum price is 12€. Quite a difference. When I add up these pricing differences, Tresorit is 2-3x more expensive than Wuala, so the 10€ price is comparable only in Tresorit's marketing materials.
So as far as I can tell, average family is still unable to obtain properly encrypted online storage. Reasonably priced solutions all come with weak legal or cryptographic protection for personal data. Tresorit is too expensive. Wuala can no longer be trusted. SpiderOak is not really sync. It's more like a backup with some extras. I wouldn't trust precious family media to Mega. I will go with Wuala for now. It's the most functional and secure solution within my budget. No recommendations from me for Tresorit until they fix their pricing.