They're about as good as you could expect from a major cloud storage provider. In theory the encryption means that Mega can't access your files, but they're expressly very cooperative with government agencies so don't bet on anything you put there being entirely secure. I haven't heard of any major problems with them though - it's what I've been using for cloud storage the past few years and I haven't had an issue. As long as files aren't shared and therefor at risk of being reported there's not much to worry about, though in the case of things getting reported it's a 'take down first, ask questions later' type deal.
Alternative take: You don't have to trust them (and shouldn't). Encrypt your uploads before you give them to Mega and don't rely on them to do it for you. Use GoCryptFS or Cryptomator on your folder and show the transparently-encrypted folder to Mega.
KimDotCom’s original MegaUpload did get shut down after a police raid. However, he rebooted the site with zero knowledge encryption 2013. The new site is mega.nz and it’s been running for quite some time. You can read about it here.
Ive been using mega for over 6 years already, haven't noticed a problem at all. If u are fed up of their downloads/uploads limit, theres an opensource project on github called (Megabasterd) , it allows u to download any amount of size of contents hosted on mega cloud for free without paying up for their subscription.
U can additionally use proxies(proxyscape) to speed up ur download speeds upto 100s of mb/s.
oh man i havent read the word Megabasterd in forever, that shit was awesome back in the day. It still works? I just cycle thru my vpn untill i find a clean one
I don't know what you have in mind with "trustworthy", and about what, so maybe this comment is worthless for you. But I've been using their cloud storage for several years (like other commenters here), for work-related files, and to sync them between computers and phone. Their syncing system and apps are actually great. No complaints on my part.