I think you will like the mustang. I have been carrying one for several years now with no problems. At first I too was leery of the plastic parts, but so far so good. I carry mine in an ibw holster. it is small enough to conceal easily. If you want to change out the plastic parts google jack first. they had the replacement guide rod and trigger last time I checked.
I got a safe shelf full of them and think they shoot great!
However, if you think it doesn't shoot great (misfires, ejection errors, etc. ) then try the kit on brownells.com to replace the spring and plastic parts. If yours is truly NIB, it should shoot like a dream. Be careful with the ejector when you reassemble the gun.
my LGS had two in the store a few weeks back. I posted about it because I don't see too many, but I thought the price was a little high. He was asking about $750. They were gone on my visit last week. I have one so it didn't hurt my feelings, and I'm really glad now since Hopalong was able to purchase one much cheaper.