Bought my 15" MacBook Pro in November 2011, and the Retina wasn't available. I was disappointed when the Retina came out, until I researched it. No optical drive (I burn DVDs for clients, as well as enjoy watching and copying my DVDs). Non upgradeable drive or memory. Also, while most software has been upgraded to Retina, there is still work to do.
My total investment was under $1950, including tax, and that includes 16GB of RAM, a hybrid Momentus XT 750 GB drive which combines FLASH with a 7200 rpm drive with 6 Gigabit Link Speed. Mine is a Quad Core 2.2 i7. Current non-Retinas are 2.3, and the current 15" Retina starts at 2.4, which processor is only 9% faster than mine, and only 4% faster than today's non-Retina.
If you do both of the above upgrades on a non-Retina today, the upgrades cost about $200 TOTAL, which keeps the price under $2000 INCLUDING the upgrades, and you have a 2.3 instead of a 2.4 processor Quad Core i7.
Try configuring a 15" Retina with 16GB of ram, an optical drive, and at least 750GB of storage. Any modified Retina MUST be ordered through Apple, so you have to pay sales tax. Total price before tax is $3178, and in California it would cost me $3464 with tax.
Is it faster? Yes.
Is it worth over $1500 extra? I think not.