I shoot a PSE nova. The biggest disadvantage to PSE is their lack of adjustability! Whether we're talking adjusting the draw more than 1.5" either way, or draw weight PSEs are just not good in that department. Other than that I love the bow!

You don't mention the age of the boy...I would guesstimate that 50lbs would be a tricky start for a kid around the age of 15, with 40 being much more in the ballpark, just a guess though. I didn't hunt at that age.

There are many cheaper bows than PSEs that have far more adjustability in draw weight and even come with extra cams...such as martins, I'm sure there are others as well.