it uses a different pos algorithm to that of the likes of nxt, which is also different to that of the likes of blackcoin. in peercoin, as far as i know they use checkpoints created by developers which is effectively the devs enforcing nodes to only download the version of the blockchain that is deemed to be "the correct chain". by rights, in a decentralized system it should be the nodes that decide, without human intervention of any kind, which chain is the correct one through consensus rather than devs enforcing this with checkpoints. i admit i havnt researched peercoin enough so i may be wrong on certain points but that is my understanding of peercoin however that is enough information for me to know that ppc will never surpass bitcoin. other pos systems dont use this version of pos and also dont have these types of checkpoints. they do have checkpoints(some only temporarily) but they are not centrally controlled as is the case with peercoin.

also a slightly better version of bitcoin would never be enough to supplant bitcoin. it needs to be vastly improved upon before it will be surpassed and overcome bitcoins (more powerful than many think) network effect.

if i am wrong, please supply some form of explanation as to how i am wrong. if i am id be interested to read how it actually works, its been a long time since i read up on it so perhaps things could have changed since then.