I just picked up a pair of these. Not too bad at 500g they feel a reasonable weight considering they are bloody huge. I've always liked V12 Mags for XC duties, MX 30s are pretty good all rounders too, but I wouldn't touch 50/50s. I picked up a brand new pair in the shop once and they felt like they'd been abused for 3-4 years, rougher than a badgers arse. Infact thats unfair, I'm sure a badgers ass aint that rough.
Got some £40 Wellgo ones with sealed bearings etc. B38s i think they're called. B something anyway. They're not heavy, grip well (much much much better than V12s), and spin smoothly. I wouldnt want to pay more than £50 for something thats inevitably going to get bashed into rocks hundreds of times throughout its life.
I'm using 24 Bicycles Toaster pedals. They weigh in at 635 grams but I don't care! They have lasted me over 5 years and still run smooth. They are by far the most comfortable, strongest, grippiest pedals that I've ever had the pleasure of stomping my feet on.
I've bought quite a few sets of pedals over the past 5 - 6 years from various brands including; Azonic, Shimano, 24 Bicycles, Wellgo, Powerplay, Tioga, DMR & Brooklyn. I keep going back to my trusty Toaster's though...