I bought one not too far back. I like how it felt in hand, and the trigger was a lot better than comparable models. The only thing I've done to it was to put a bit of white acrylic paint on the sights with a toothpick. It made a huge difference in sight visibility, especially in lower light conditions.
I think it's a blast to shoot. I've started reloading with cast bullets for it so I can shoot it a lot more. I've had no problems with my clips, except that the first time I loaded each clip, I had one failure. After that, it's been smooth sailing.
Can't say about the extended mags. I've been happy with the 2 that came with mine, so I haven't really looked for them.