Usually when I see people complaining about not getting paid the correct amount after mining for so-and-so hours on a pool I assume they simply don't understand how mining works (I know, because I was one of those people not too long ago) so I hesitate to make a similar complaint, but...

I pointed a single GTX 1080 at the VTC pool on Give Me Coins for 24 hours and the hashrate reported by the pool and the miner were in close agreement (around 48 MH/s). In that time frame I should have earned 0.9 VTC, which is exactly what I needed to round up my wallet to the next higher integer (the 0.1 was triggering my OCD something fierce). Granted, a block has to be found to get credit for your work, but as long as a block is found one should get credit. As the days tick by since that 24 hour run of mining my balance has sat stubbornly at 0.48 VTC and, yes, blocks were found during and after my mining session.

So as of now it looks like I got shafted out of 50% of my earnings, which, sadly, seems to be a common occurrence with VTC pools in general.

I should note in the interest of fairness and to illustrate I don't have an axe to grind here that I also occasionally mine FTC on GMC and get more or less the expected earnings for a given 24 hour time period using the average difficulty on whattomine.com. So this doesn't appear to be nefarious behavior on the part of GMC, unless they just happen to hate VTC miners for some reason.