Hey again everyone I have a few more more questions regarding mining altcoins.

1.  It has come to my understanding that proof of stake may be implemented into Ethereum in the next few months. I know there are other altcoins but are any of them worthwhile to GPU with at least 80-85% of Ethereum profit?

2. I thought the Radeon RX 470 was currently one of the best Ethereum miners on the market for the past year, but it looks like the 480 is more profitable. I know that GPU's are getting better every year but I heard people talking about interesting new GPU's coming out in the next few months. Is it worthwhile to wait until something better comes around or will the RX470 be the best bang for my buck for the next 5-6 months.

3. Why do different people use different GPU's for mining? I know it's about preference but isn't there always a clearly top card that has the best price for the speed?

4. What's the difference between 4gb versions of cards and 8 gb versions? I get that the bigger the better but they often have a 40-50$ difference between them. Do they majorly impact the mining speed?

Ps. I know that google is my friend but with so many opposing articles and arguments online I would rather hear this directly from the people on this forum.
All answers and advice are greatly appreciated.