Ford may have stolen last week's auto show in Detroit with a sexy sports car -- but GM CEO Mary Barra countered with a new electric car, the Chevy Bolt, which could turn out to be a lot more significant in the long run. Source: General Motors. 

What a difference a decade makes!

Less than 10 years ago, Ford (NYSE:F) and General Motors (NYSE:GM) looked doomed. Ford mortgaged everything it could in 2006 (including its famous blue oval logo) for a loan that would give then-new CEO Alan Mulally the resources he needed for a long-shot attempt at saving the company. 

Meanwhile, GM tried its own Hail Mary -- but it fell short as the 2008 economic crisis hit, and GM famously (or perhaps we should say "notoriously") crashed into bankruptcy court. 

Now, though, both companies are in good financial health. Both have made huge strides, with much-improved products and cost structures. But which is the better bet for investors right now? Two of the Fool's top auto minds, John Rosevear and Daniel Miller, offer their views below. 

Daniel Miller: Why I like Ford right now
Let's get right to business with the most well-known factor: Ford's upside. 

Ford's upside spans the globe, and in multiple ways. First, while Ford trails GM in China in terms of overall sales, its sales have been surging over the last couple of years. In fact, Ford and its joint ventures sold 1.11 million vehicles in 2014, the first time the automaker surpassed 1 million in sales, which was good enough for a 19% gain compared to 2013. 

But Ford's upside isn't limited to sales in China. The automaker is pouring capital into its luxury lineup that will help increase top- and bottom-line performances, and recently took a leap ahead of the competition with its forward-looking aluminum-bodied 2015 F-150.

Ford's new-for-2015 F-150 began rolling out of its Dearborn factory in November. Early demand for the new truck has been very strong. Source: Ford Motor Co.

Also, Ford has made outstanding progress on two of its most critical obligations: automotive debt and underfunded pension plans. As recently as 2013, Ford's pension plan was underfunded by $18.7 billion -- an obligation valued at more than its automotive debt. By the end of last year, however, that obligation was cut nearly in half, to roughly $10 billion. Meanwhile, Ford's debt is expected to be down to $10 billion in the near future.

For context, this means Ford's balance sheet is in better shape than it has been in over a decade. Also, and more important, this gives Ford the ability to use cash that it used to spend paying down debt and funding pension plans to dish out to shareholders instead. Consider the fact that Ford paid out $2.7 billion in dividends in 2012 and 2013, while it spent $8.4 billion paying into its pension fund alone. Going forward, Ford will spend only a fraction of that amount on its pension plan, which frees up enough capital to triple the value returned to shareholders in the near future.

Now let's talk about the competitive advantages that Ford has over GM. First, just this month IHS Automotive announced its loyalty awards,giving Ford top honors for "Overall Loyalty to Manufacturer" and "Overall Loyalty to Make." That means that more consumers who buy Ford later purchase another Ford than happens with any other brand. That's a huge competitive advantage.

Another huge advantage lies with Ford's credit division, which essentially acts as a bank. Ford Credit takes massive amounts of capital and dishes it back to consumers and dealerships, making a significant profit in the process. In fact, Ford Credit is Ford's second-most-profitable entity outside of its North America region. No other automaker has anything close to Ford Credit, and it will remain a significant advantage going forward.

When you invest in a company, you're placing your trust in management to make the right decisions and increase the value of its business. Ford has one big trick up its sleeve that GM does not: family. The Ford family interests are aligned with those of everyday shareholders, as the Ford family, including Executive Chairman Bill Ford, are exclusive owners of Class B shares. That means that what's good for the Ford family is good for us shareholders.

Furthermore, Ford's management has proven extremely capable in the worst of times. Consider the financial crisis that brought crosstown rivals Fiat Chrysler Automobiles and General Motors to bankruptcy while Ford survived on its own dime.

The choice is clear: Ford is the best bet for investor dollars in Detroit. 

John Rosevear: The case for General Motors
In a way, I can't lose here -- I own both Ford and GM stock, and I think both companies are poised for good things over the next few years.

But for new money right now, I think GM might be the more interesting bet. GM got pretty badly beaten up in 2014 (rightfully so, I'd argue) over its massive and expensive recall scandal. New CEO Mary Barra's sluggish initial response to the mess didn't help.

But Barra got with the program and made some strong moves, using the crisis as an opportunity to push for some big changes within GM. Those changes should make the General much more responsive to safety issues from now on, and they'll only make GM's future products even better.

Cadillac chief Johan de Nysschen promised last week that the new Cadillac CTS-V would beat the German luxury brands at their own game -- and GM's recent track record makes that a very credible threat. Source: General Motors.

But while the recall mess grabbed the headlines (and dented GM's stock price), GM's underlying business looked really good last year. GM has made huge improvements to its most recent products, and that means GM's dealers can sell them without the fat discounts GM had to resort to in the past. That in turn means GM's profit margins in North America have soared: Factor out the costs of the recalls, and GM's operating profit margin in North America was 9.5% in the third quarter -- better than Ford's, and better than a lot of rivals'.

As the recall drama fades in the rearview mirror, these improvements will start to become more visible to investors. Meanwhile, Barra and her very sharp team continue to whip other parts of GM into shape. Its money-torching European operation will turn a profit in 2016. Its solid profits in China, where GM's sales are second only to Volkswagen's, should only get fatter as it adds more SUVs and luxury cars to its mix over the next couple of years.

And as "innovation" becomes the hot auto-industry buzzword, the brilliant GM research and development department that its rivals have always feared is stepping up in a big way. From self-driving cars (GM's Super Cruise system will be on the market within two years) to radical weight-saving construction techniques (among other innovations, GM has a patented technique for welding aluminum to high-strength steel), GM is showing that its long-admired potential is finally being harnessed.

In a nutshell, that's the reason to buy GM. For years, industry observers have said that GM could be a profit-minting powerhouse if only it got its act together. Now, under Barra and her team, it's finally happening -- and 2015 could be the year when the world finally catches on.