BTC mining seems to be a minor part of the pool, it's almost all altcoin mining, so no idea why you posted this in the BTC section.
They make claims about running a pool since 2014, but state clearly in the FAQ
Q: How does the pool determine my payouts?
A: This pool uses the following payout system. (PROP)
Only a pool who has no idea what they are doing would use Prop ... and for 7 years also.
Prop is easy for short term miners to take rewards from long term miners due to the flaws in the Prop payout method.