I was talking to the wife about one version of these just the other day. I remembered the special hoppers they made to charge the balls, basically an Apache loader with the insides chromed (to reflect more light - here it is
) and the stirring implements taken out to be replaced by lights. So you spent a lot of money to get the performance of a $5 "slap agitated" hopper. Tracerballs were popular for about a year or two and then everyone remembered, after playing one night game, that night games suck, period, and Tracerballs went back into the annals of paintball history.
Give it another 5 years, and they'll be back until everyone remembers night games suck and Tracerballs will go back under, once again. In all of the years I've played paintball, I've had exactly one enjoyable night game, and all of the rest of them were anything but. Night at the field is best spent drinking and BS'ing around the campfire, trust me.