I typed out a ridiculously long winded post but accidentally closed my browser before I could finish and post it, so here is the short version.
Will you be using your sidearm a lot? Consider how much use you will be using it before you decide on a brand. If you will be using it casually, by all means purchase the KJ as it is a fair quality item at a fairly low cost. If you will be using your side arm consistently and constantly I would suggest purchasing a gun from KSC or Tokyo Marui as both companies have easily sourceable replacement parts and enhancement parts for a majority of their line ups.
"Its only a little bit on fire"