I've eaten there twice in the past year. It's alright, but nothing worth much notice in Las Vegas.
One quirk is that Siegel Group, which runs the Gold Spike and a number of other non-casino apartment buildings around town, has some sort of weird voucher program for its renters whereby they can eat some of their meals in the Gold Spike's diner. Maybe one meal a day. I don't get exactly how it works, but I always see lots of single guys (parolees?) eating there off a special, lower-quality menu, and paying with Siegel vouchers. Think grilled cheese sandwiches and bowls of chili rather than club sandwiches and strip steaks.
Just...weird.