Less RAM and an SSD vs. more RAM and an HDD? This isn't a question about which part of my computer to upgrade. It's a question about what I should buy in my eventual new computer.

I have an early 2011 13" MBP with a 500GB hard drive and an upgrade to 10GB of RAM. Now I'm starting to look at buying a 13" rMBP with a 512GB SSD, and I'm torn between paying more for the 16GB model or sticking with 8GB, keeping everything else constant (i.e. that's the only part I'm indecisive about). I remembered that a while ago, something I read said that having less RAM but an SSD is comparable to having more RAM and an HDD. Is this true?

Specifically, if I've grown used to working on 10GB of RAM, could I get the 8GB rMBP and not experience any serious performance drops because the storage that the RAM is drawing everything from is still so much faster than what I'm used to?
It all depends on what type of usage your rMBP will be subjected to. It does help with the SSD and just cutting it off at 8gb(I had a similar setup but with the earlier 15" rMBPs) if you're trying to save some money but make sure you have enough storage on the SSD(you'll run out fast). Not to mention 2011 RAM speeds are significantly slower than today's.