3 months, 1 year or more doesn't really matter as with a typical MorphOS usage pattern it will be long out of warranty before it fails.

FusionDrive is 100% SW btw (tried it on a MPro before getting a proper sized SSD) and with a large enough SSD part it will move stuff on and off.

Another option are Hybrid drives, had a smaller Seagate in my PMacG5 when it was regularly used. Well to be honest it's still in there and will be for the foreseeable future for being completely stuck in the drive bay.....