Personally I'm invested in PIVX, cause I have the feeling they could pull a DASH this year.
There aren't many interesting PoS options besides PIVX in the privacy coin space.
XSPEC would be another on with stealth staking, but I don't hold any at this time.
What do you mean 'pull a dash'?
DASH made x100 in 2017, but I know repeating that is optimistic.
DASH had a market cap of 80 millions at the beginning of 2017, PIVX is at 340 millions now already, so give it a x20-30 if it reaches reach 10 billion in 2018.