I run a super cheap Dell Perc 6i w/bbu, a sata adapter cable and right now 4x2TB drives in a 5.5TB RAID5 array, not the best performance...but solid for what it is, doing Plex library files, and hosting 6-8 running VM's with a wider variety of tasks, and I have 0 issues. As said above a BBU is critical if getting a RAID card. In my experience with my home RAID...the battery became discharged and the array went from write back to write through mode...and struggled to write more than 4-5MBs. It was horrendous. Resolved the issue with a few firmware and BBU freshly charged, I do plan to go to a 6 or 8-drive RAID6 in the future.
I considered 4TB drives until I did some more research and finally had to fix a large array that another IT company had sold a school we recently gained. Didn't help the school was non-stop accessing but it took the better part of a week to actually successfully rebuild the array. Guess what happened a couple weeks after that??? Yep...another drive failed. Thankfully we had talked them into a NAS backup system with a RAID6 array and are now rebuilding their server array this summer. Ticking time bomb until then though... 4+ TB drives in an array are for those who are patient and have really really good backups and possibly a failover data store/server to keep them alive during the long rebuilds that will happen.
Honestly I get some of the white label enterprise 2TB HDD's off of fleabay, or a seller that also sells there rather and keep a couple extra on hand because they are cheap enough. The array rebuild took around 6 hours when I had one drive fail. But I gotta keep a tight budget and so far I can't complain with the performance of these drives. The one that failed came with the 4 I bought off of a fellow TPU-er that had used them for years so I expected a failure and the price was fair that I had no complaints in cheaply replacing one.
I do run a backup with a Server 2012 R2 Storage Space (testing purposes more than serious deployment...) setup using 2X2TB and 1X1.5TB...not in any kind of redundancy mode (so damn slow...)..and I needed the space to allow for incremental backups which I didn't have with redundancy. It works well enough, I get SMART report notifications through Event Logs so I'm not worried...but I also sysadmin my site and network
Not saying my setup is the best, but in a home lab situation the old-ass cheap-ass Perc 6i's + white label 2TB enterprise drives in a RAID 5/6 is a good way to go in my experience. I was able to buy a spare Perc 6i for around $15-20 shipped...and sure it's old tech, long replaced by H700's and beyond...most folks won't notice what they're missing unless they went with SSD array's or SAS drives in the first place...and then you're not in the cheap-ass budget price point anymore anyways.
I agree, even with an array one should backup...but with an array with redundancy and parity hopefully the backup is a "rather have it and not need it" kind of situation. And at least if a drive (5) or two (6) fail in the array, keeping a couple spares on hand...shit can be fixed in a night, day or two. It is all good experience...if someone is truly serious about their data...then being cheap isn't going to solve anything. If I lost all my data I'd be pissed...but I also plan to increase the array, change to a 6 and I'm building up a secondary storage array for backup purposes. We shall see. To each their own.
My core server, my VM's including the one that runs Plex, Teamspeak, RDGateway, etc. etc., runs great with this array. I run the core OS on an old Samsung 840 120GB SSD...everything else on the array, and the backup on the Storage Spaces combined volume. So far works great, super stable. I guess it depends on what direction you want to take...mine is kind of overcomplicated for what it needs to be...but I'm gaining experience on stuff I need to support professionally, and am able to make things work in my budget which is a win-win for me!