Brands would certainly promote good things about their products. Its up to the smart consumer to choose wisely.

Price differences are because of 2 things imo :
1) Over advertising
2) Extra ingredients in the supplement

No.1 is what you would want to look out for. Brands that sell their product at higher prices just because they have to pay endorsements to their fleet of pro athletes may have the same nutritional values as another that has less to pay for advertising. The next time you read an article, or a pro athlete commenting or recommending a product, check to see if they are endorsed by any of the supplement companies.(you'd be surprised how many actually are)

No.2 is the value for money bit. Yes, some brands cost more because they actually have MORE in it. For example, BSN's Synthia costs almost twice as much as Optimum Nutrition. But check the in depth nutrition info. BSN's Synthia has more amino acid blend content compared to ON and other added ingredients.

At the end of the day, weigh your goals and budget. Then see which works would suite you best

girth? like penis girth??? LOL

Yeah, like I said different products have different amino acid blends.

BSN Synthia also has a mix of whey, egg albumin..etc for timed release. Again, when are you consuming these protein supplement? If its early in the morning or post workout, you would want to go for pure whey isolates instead of a blend simply because your body would need a quick supply at those times.
Also, if you go for standard whey protein, you could easy get the 'timed release' effect by using milk to make your shake instead of water. Peanut butter would be a good add too.

PRO Complex and such proteins that offer timed release are better taken at night before you go to bed so that you have a steady release of protein throughout the night.

Yes, of course casein would be the better choice for slow release protein. I am comparing normal whey powders to blend powders. Since the pro complex you were referring too has timed released proteins, it can also be used pre-bed.

But seriously, protein is just protein at the end of the day. Stick to normal whey and spend on real food.