I got my PIO card way back in 2001 when it still cost 1000 USD for 20years and now feel like I've been taken for a ride. The new PIO card became cheaper and now this OIC business.
The only good points about the OIC I can see is the waiver of the registration requirement and the indenfinite validty. Otherwise it is just a PIO card. Surely they will introduce the facility to access the separate line later.
The PIO separate line is available at all indian immigration lines, only it is not explicitly posted. I have jumped the queue each time and when intercepted I just show the PIO Card/booklet. The even allowed my companions to jump the queue with me. Plenty of bewildered/angry looks from the folks in queue though.