Would you trust important data on a battery-powered volatile storage?
Of course, anything of real importance is also copied over to the Raid box, and also part of my Dropbox folder.
Getting back to OP's question... I tend to agree with his thinking. While the mainstream SSDs are generally too young for us to have an accurate idea of typical lifespan, it's reasonable to assume that an Acard ramdrive should outlive them all. I would expect that the internal backup battery would be the first thing to go, but a replacement is child's play, and size isn't critical as long as you get the right voltage. It's a Lithium Ion, but simply connects with a 2 pin quick connect, similar if not identical to the ones used on user-replaceable cordless phone batteries.
Keep in mind that the Acard units come with some inconveniences:
1) having to keep the system on to keep it powered
2) relying on backup battery (with 4 LED meter) when power goes out
3) reinstalls when 1 and 2 are exhausted
There is a CF slot on the front to do backups/restores with, but the couple of times I tried that (with early firmwares) I couldn't get it to work. I've put two firmwares on since then, and never tried again. With OS installs being so easy on Linux as I mentioned above, I don't bother.
That being said, it's nice not ever having to worry about performance slowdowns or how many writes are going on. The real question is how much that's worth to you and whether there's a better bang-for-the-buck solution out there using combinations of other technologies that are dropping in price faster than Acard units and DDR2 (which is going UP in price).
Edited by Kelstertx - 1/10/11 at 12:37am