It’s like falling in love all over again.

After trading closed last year, I lauded credit card stock Discover Financial Services (NYSE:DFS) for its great mix of value and growth potential.

Discover certainly didn’t let investors down. It has kicked 2012 off with a nearly 40% run in three months, sending it to all-time highs above $33 per share and extending its almost 500% turnaround from the depths of the financial crisis! By comparison, during this latest bull run the Dow is up a mere 7%, the S&P 500 12% and the Nasdaq 19%.

And because I can’t resist taking a jab at my boss, InvestorPlace Editor Jeff Reeves, DFS has nearly tripled the returns for his pick in our Ten Best Stocks for 2012 competition, Alcoa (NYSE:AA), which is up 14% year-to-date.

But considering that Discover has grossly outperformed the S&P 500 (and its sector mates) and actually is nearing my original price target for all of 2012, it’s time to take another look at DFS: Has it gassed itself getting this far?

In my original argument, I felt Discover had a number of things going for it, but the big ones were:

• Fantastic growth opportunities for the credit card industry as a whole — specifically in emerging markets, though there’s still plenty of growth left in the U.S.
• The company’s product strength, particularly its popular cash-back rewards.
• Discover’s consistent string of putting out Street-beating earnings, including some serious expectation-crushing results during the past year.
• DFS’s fantastic valuation, both on its own and compared to its industry rivals.

And following last week’s earnings report, I’m proud — and admittedly surprised — to say we’re still 4-for-4 on those fronts.

Getting to the news first: After a relatively weak beat (by 4%) on its previous earnings report, Discover absolutely crushed its first report of 2012. Fiscal first-quarter earnings rose almost 36% from the year-ago period to $631 million, or $1.18 per share — 25% better than the 94 cents per share Wall Street expected. Discover was bolstered by higher credit card spending and loan balances, but it also got help from a greater-than-expected release of loan-loss reserves. Delinquency rates continued to trickle lower, too.

The earnings call had plenty more good news. Discover announced a $2 billion stock repurchasing program — a sequel from last year, when it bought up about 18 million shares for $425 million. Executives said they expect 10% to 15% annual EPS growth, and declared the company was financially sound enough to make moves like acquisitions and dividend hikes. That last part is encouraging, considering the current 1.2% yield is OK, but won’t induce salivation.

Analysts have been jacking their expectations up since then. Within the past week alone, earnings estimates for Q2 have gone up from 90 cents per share to 92 cents, and current fiscal year estimates have increased from $3.57 to $3.89. And just a couple days ago, Guggenheim upped its price target for DFS by about 12% to $38.

It almost seems crazy to say, but after its nearly 40% run this year, Discover still is a solid value play. It trades at 7.5 times trailing 12-month earnings — vastly less than Visa’s (NYSE:V) and MasterCard’s (NYSE:MA) 20-plus valuations — and about 9 times expected 2013 earnings, almost half that of its rivals. Again, even if you split the difference and DFS’s price-earnings ratio froths up to around 13 or 14, you’re still looking at 50% gains at $50 per share.

And the prospects for growth pretty much remain the same. Discover’s cash-back rewards remain attractive to U.S. consumers, who might be in a recovery but certainly don’t all feel like it. But most important, emerging markets have much more room for plastic — with China alone a massive source of potential.

China has roughly 270 million credit cards in use — already five times as many as in 2006. While that’s only about a quarter of America’s billion-plus cards in use, Lafferty Group Chairman Michael Lafferty told USA TODAY that China will surpass the U.S. as the largest credit card market by 2015. Citigroup (NYSE:C) certainly sees the possibilities, and celebrated governmental approval in February to issue its own cards in the country without having to piggyback on a Chinese bank.

It’s at least worth noting that Discover is far from immune from a broader economic and stock market downturn. And buying in now certainly would smack against the belief that you should “sell at the top” — especially when that top is an all-time peak.

But if you think the market still has room to run — heck, even if you don’t — Discover continues to offer a 1-2 punch of value and growth that should see things through.

Kyle Woodley is the assistant editor of InvestorPlace.com. As of this writing, he did not hold a position in any of the aforementioned securities. Follow him on Twitter at @KyleWoodley.