I've been gathering info on RAID, as I need to get a new NAS that'll accommodate different types of data including databases and user homes (they have to be on the same machine, budget restrictions). First and foremost, RAID is old, obsolete and should die. Still, there are few other solutions and RAID is the most common by far, so we have to live with it.
Now, in regards to sw vs hw RAID, the argument isn't a simple one.
It's not a matter of "sw raid is innapropriate for a production evnioronment". If you ever lost a controller, had to wait 2 weeks to get oa new one and hunt down older firmware because the more recent one doen't recognize your array, you'll be wishing you had sw RAID, I can promisse you.
It's not only performance either, because a good hw RAID can give most sw implementations a licking... but not always.
It's not cache + batteries either (oh, also, batteries die), because lack of cache is a real problem with RAID 5 for instance... not so much for, say, RAID 10. Also, if you say stuff like sw RAID isn't fit for procduction and use something like RAID 5... but I digress (and bashing RAID 5 is beating up a dead horse)
It is, mostly, a matter of cost. True, hw RAID can be better for some applications, just as sw RAID is better for others. There are a huge number of discussions on the matter online as to which applications should use which implementation. Still, when I am installing a system on a machine that has no RAID card, I like to be able to rely on "good" old mdadm. For instance, on my test server. When I use proxmox on such a machine, I'm gonna have to waste a couple of hours just to get a raid setup, copy the info to it, resize LVMs and fs, etc, and I'm gonna end up with a config that you recomend against. I recognize the risks you presented, I evaluated the and accepted them... just like I did when I chose proxmox in the first place. The difference is, I had way more trouble then I should, just because you chose to impose the no sw RAID rule. It's your perrogative, I know, and proxmox saved me quite some work later on, but why should't it also have given me the liberty to choose for myself wether or not I wanted sw RAID? I don't want it out of spite, I need it because I have no other alternative.
So, please, consider including this on your standard install. Label it an "expert" install option if you have to, but please, make this wonderful tool even better by including something many will surely find useful.
In the meantime, I'll be in the corner fiddling with Solaris and ZFS. Now there's a decent raid-like implementation