Hi there! First off, Palnet.io is not my site. Its run by the people behind @minnowsupport who are made up of some of Steem's top witnesses and community leaders.

Yes, staking is the same as powering-up. So, if you stake all 436 PALCoins, you'll have 436 PAL Power, which works like STEEM Power. Of course, you can also just go to Steem-Engine.com and sell your PALCoins for STEEM, if you want.

No, using Palnet.io or staking your PAL Coins will not take away your STEEM Rewards. Palnet.io and its token is still built on top of the Steem blockchain. It doesn't replace it. It just adds to it. So, you'll get both STEEM/STEEM Power and PALCoin/PAL Power Rewards when you post in Palnet.io.

The difference is that unlike Busy.org, or Steempeak.com, or Esteem, and the other frontend apps which are essentially duplicates of the content on Steemit.com, Palnet.io only shows content that uses the 'palnet' tag. Palnet.io also has a different set of rules like its rewards structure, etc. But these only affect you when it comes to your rewards and behavior in Palnet.io, not in the rest of the Steem Blockchain.

@clayboyn actually said this best in his post about palnet

The great thing about PALnet is that we're not asking anyone to leave STEEM. We aren't forking and taking any of the community with us. Our posts will still show up on STEEM and work like normal, which means we can aim to correct the distribution problems without negatively impacting the STEEM community or expecting anyone to "give up and start over." In short, we provide an alternative token and front end that removes what many of us feel are the problems and allows for users to grow and earn stake, which ultimately allows the community to determine what content it wants to support.

So, if you post using Palnet.io or using the 'palnet' tag, it will show up in both Steemit.com (and other frontends) and in Palnet.io. It will also get rewards in the form of STEEM and PALCoins.