My experience so far.
So I originally purchased my 15-inch Macbook Pro 2011 from an approved retailer in the UK and didn't have any issues with it up until a few weeks ago when I started experiencing the graphics issues that everyone else has explained in this thread. It started as an occasional crash but eventually got to the point where the Macbook became completely unusable and couldn't even be booted up in any mode.
Soon after purchasing the Macbook, I upgraded my HDD to an SSD, upgraded the RAM to 8GB and then, a couple of years later, replaced the Optical/DVD Drive with a 2TB HDD for additional storage.
I was relieved to hear about the repair program and that Apple had finally acknowledged the problem. I backed up my disks and took my machine into the Sydney Apple Store in Australia where I now live and explained everything. They booked it in for the repair and explained that the logic board would be replaced free of charge to fix the problem. As I have followed this thread for a few months and read most of the posts, I was armed with a bit of information and queried the effectiveness of swapping out the logic board. The Genius assured me that this would fix it and told me that all of the parts would then be covered anyway even if anything were to fail again. I explained to them that I'd swapped out the HDD, RAM and Optical drive myself and they said this was fine and didn't effect my cover by the repair program. Also, buying the Macbook in a different country to the service Store didn't matter. Happy days.
After a couple of days I picked up my repaired Macbook and immediately tested it when I got back home. As soon as I connected it to an external display (projector), it crashed. Disaster. The repair had apparently done very little to address the problem. I could now at least turn on the laptop so I knew that the part had been replaced but, when using graphics intensive applications, I was getting the same screen distortions and crashes I had a few weeks back when it all started.
After returning the Macbook to the Genius bar and explaining the failed repair, the technician seemed very bemused and explained to me that I was the first user to complain that the logic board replacement hadn't fixed the problem. He told me that he would arrange for another new logic board to be fitted as a priority and would report this case to management as they would want to hear about it. I asked what would happen if the second logic board didn't fix it and he told me that, if that were to happen, he would need to escalate the case for further review. He was very apologetic and didn't hesitate to book it in again.
I'm due to pick up the Macbook tomorrow morning following its second repair and will this time sit in the Apple Store testing it before I leave. Using gfxCardStatus to switch between graphics cards and running Photoshop and other graphics intensive apps, I'll see if the same failures occur with a second new logic board. I'm no expert but surely if one replacement didn't work, another one won't either? Could it be that the replacement was faulty as well? But straight away and not after years of use like the last one?
What's that Einstein quote?: The definition of insanity is doing the same thing over and over and expecting a different result...
I'll report what happens next but I think I've seen a few people mention that after 2 or 3 part replacements, it's Apple's policy to replace the whole machine? Does anyone know if this is the case?
It's all been a bit of pain but I'll be satisfied if I either get a working machine or new replacement Macbook at the end of all of this.
Thanks to all who have contributed to this thread. It's been a great help, source of information and reassurance.
Cheers