I have had my cyp unitas for well over a year, I originally purchased a group of 9 fry which turned into 6 males and 3 females, back a few Septembers ago. I had one smaller female who never grew as much waste away, and I lost another female after stripping fry from her (first time I ever stripped a fish). I then purchased another group with 3 adult females and 4 males to bring my totals to 10males and 4 females and have not had a single cyp death from that batch, been amost a year got them last February.
In conclusion of the 16 cyps I purchased I had one waste away and one die from my inexperience, but other than that they have been a hardy variant. I also have about an 80% fry survival rate and only lose a couple per batch I collect.
Paracyps on the otherhand, have been a different story and seem much more prone to wasting.
I've only had mine for about 6 weeks. So, it's too soon for me to have an opinion. However, if you didn't run across it yet, I posted a similar question shortly before I got mine. It might be worth a read: Are Cyprichromis worth it?