For about 2 years now I've been using CrashPlan Family Unlimited (no link because I'm mad at them) to handle backing up my data. I liked the solution well enough - it had Peer2Peer backups which meant I could install it on some less-tech-savvy friends' & families' computers and they would have backup. It also supported Linux and allowed multiple computers (any OS) to use the same account which meant I could back up all my stuff and my wife's (6 computers, split 3 win/3 linux). Well they recently announced they are no longer going to offer their crashplan for home service. Their solution is to either offer a deal with Carbonite (no linux support) or their CrashPlan for small business. They are offering 75% off for 1 year for their small business plan, which comes out to the same price as the old $150/yr for the family unlimited plan for the first year.. afterwords it's 4x the cost. So I've decided they are no longer going to get another penny from me.
I'd love to switch to Backblaze, but they don't offer a Linux client, no peer2peer and the cost would be more than what I was paying previously ($50/yr/computer). So I just spend the last hour or so (so much for getting work done... thanks for nothing CrashPlan) looking at various solutions that support Windows and Linux as well as peer2peer.
I've narrowed my search down to the following products. I haven't had a chance to evaluate them other than looking at their web pages.
Spideroak One
This is the only product I found that provides the cloud storage as well as the software. It supports Windows, Linux, OS X, Android and iOS (not sure if it does the backup on the mobile stuff or just access). Pricing for my storage needs would be $279/yr and it doesn't support peer2peer.
The rest of the solutions all use a cloud storage provider such as Amazon Glacier, Backblaze B2 or Google Coldline.
Duplicity
Linux only, rsync like backup solution. Free, GPL. I only include this one in case I decide to go with a Backblaze for the Windows backups. Duply is a front end. I found a guide on doing Encrypted backup to Amazon S3 (2014) using duply so that might be a good starting point.
Duplicacy
While similar in name to the previous one, it's not. This one supports backup to cloud storage as well as sftp so it has at least partial peer2peer support. For personal use, the CLI version is free for any OS, while the Windows/Mac GUI Pricing is reasonable at an initial $20/computer for the first year and then $5/computer after the first year. The source code for the CLI is available, but not sure of the exact license (not a standard OpenSource license). It's written in go so it shouldn't be as much of a memory hog I hope.
qBackup
This too support sftp and cloud storage. Pricing is $29.99 per windows/mac computer and $99.99 per linux. This is definitely a pricey option but it looks like it's only a one time fee.
GoodSync
I'm really turned off by their web page, and it's hard to find the information I want, but I'm willing to give them a try. They do have their own peer2peer implementation in addition to sftp, but it's restricted to the same account. Pricing is $29.95 for windows/mac and then $39.95 for the linux cli. They also have a Linux/Windows server, but I think that's for their management solution.
CloudBerry Backup
No idea if they have a peer2peer solution or sftp support. For upgrades after the first year, it's 20% of the original price. The offer a free version but it doesn't allow for custom retention, scheduling, compression, or encryption. Pricing is $29.99 per computer, with a volume discount on linux computers at 2+ for $24.99.
UrBackup
This product is an opensource client/server backup system. It looks like I'd have to run the server somewhere and then configure the clients to backup there. In order to get block-level changes on windows a lices would been to be purchased at $17 per windows client. There may be a way to archive to Amazon Glacier via S3, but I'm not entirely sure.
CloudBacko
They offer a free Home version that looks like it supports Windows and Mac. They also offer a free mobile version which backs up to Dropbox, Google Drive or OneDrive. They also offer a Lite version ($19 per install) that offers the ability (for $9) to do a cloud2cloud backup, e.g. backup dropbox or google drive. I think combined with the mobile version might be a good way to backup phones. The lite version also offers the ability to backup the full windows install instead of just the data. In order to get Linux Support (right now?) you need to purchase the pro version at $149 per install, in addition, Ubuntu is not listed as supported - only RHEL and CentOS.
duplicati
(added after initial post). Not much info (very little documentation even!) on the site, LGPL, supports Windows, Mac and Linux. Writing in .Net. Supports S3, sftp and Backblaze B2.
rclone
This isn't really a backup solution, but I'm including it here because it'd be a good way for me to backup things that don't change (music/videos)
Edit @22:00 because somebody pointed out I missed iDrive. Adding details here for completeness.
iDrive
Windows and Mac are supported with their personal plan, which is definitely cheaper than Crashplan was if you had less than 5TB. In order to get linux support you'll need to switch to their business solution which can get very pricey as you go up in storage requirements.
Edit 8/23 1300:
Apparently iDrive personal does support linux - I swear when I looked last night the Linux was not supported in personal. Guess I need to try them out as well. Lots to look at.
Edit: 8/26
Arq
Arq is another program that can use S3 or Backblaze B2 as it's storage. It's only Windows & Mac. It costs $49.99/user or server.
Syncrify
Syncrify appears to be a custom client/server backup solution which supports Windows Linux and Mac. Personal edition is free but doesn't support file versioning, nor encryption. Single Pro license is $49. discount after 5 licenses. Licenses are per client.
BuddyBackup
Looks like a P2P only backup. Free; only supports windows. Blog hasn't been updated since 2014.
Resilio
Looks more like a dropbox like sync program vs backup. Supports windows, linux, mac. Home version is $59.99; Family version (5 users) is $99.99. Used to be BitTorrent Sync
SyncBackPro
Windows only; $54.95. interface looks like ui hell.
Restic
Cross platform, cli only, open source, written in go.
And a whole lot more
I found this list written by the author(s) of restic. It mostly contains linux only software.. but it's definitely something I'll look at.
Backend Service
One choice with all this is which service to use for storage. Primarily I'm interested in archive type storage, so things like Amazon S3, Google Cloud Storage or Azure Storage are probably too pricey. Instead I'm interested in things like Amazon Glacier, Azure Sttorage LRS Cool, or Google Cloud Storage Coldline.
A few new ones I found in similar price point are Backblaze B2 and Wasabi. Unlike typical Cold Storage, both Backblaze B2 and Wasabi offer instant download instead of having to wait 2-4 hours for availability. Wasabi has cheaper storage at $0.0039/GB/Month (min 1024GB) vs Backblaze's $0.005/GB/Month (no min); but Backblaze B2 offers the first 1GB downloaded per day free, with other downloads at $0.02/GB while Wasabi is $0.04/GB download. The qBackup page has a decent comparison of cloud storage providers though they don't list everything available.
(edit 22:00) Oracle also offers an archive storage service which looks to be pretty competitive with pricing at $0.001/GB/month but I'm not sure the exact costs to get the data out (they have a retrieval and transfer price listed.. it may be $0.125/GB total for up to 10TB). They also have a small read/write fee for items less than 10MB of $0.05 per 1000 requests.. so that could increase the cost depending on how the backups are done.