I think the 50/50's get a bad rap from a performance standpoint because some people don't take the time to get the pin setup right. Stock, they are crap, but I found when I went with 8mm pins on the front and rear and 5mm pins in the middle row they gripped just as tenaciously as any pedal I've ever ridden. They are overpriced, but they work right if you use the right pins. There are cheaper pedals out there that perform better out of the box though.
As for shoes, I'm using 661 Filters now but will probably give 5.10's a shot in the future based on reputation. The Filters are good but I have the cleat hole hacked out and I think the 50/50's can provide more grip if I have some sole there. I really prefer a shoe that has a supportive/stiff sole for riding platforms, especially pedals that have a void space in the center. I've ridden with Vans, running shoes, and some skate shoes in the past and I felt like my foot was rolling over the outside of the pedal (I think I tend to stand on the outer part of the platform most of the time anyways), or sinking into the middle without the stiff sole. I think the bike shoes are worth the extra $ because of that feature.