good shots. i don't actually use the 50mm as much when doing portraits. when doing a single/double person shots i usually use the 50-200, with groups shots the 12-60. i think the next portrait session i do with one of the artists i work with i'm going to try the 50mm for a dominant portion.
I probably would be using the 50-200 for portraits too if I had it
Then again, the 40-150 is so light, and the 50-200 would probably be kind of an inconvenience to use...
the size of the 50-200 is not really heavy at all. maybe if you were going on a hike i could see how the weight could be an issue, but if you were just doing a portrait session it's great! it feels extremely balanced on the e-3 with grip. if you decide to keep your e-510, the ownuser grip is great for balancing out the weight. i decided to keep the 520 as my backup. the price isn't the greatest, but hey, that's what we have ebay & craigslist for.