With respective market caps of $99.7 billion and $40.9 billion, Canadian Natural Resources (TSX:CNQ) and Cenvous Energy (TSX:CVE) are two of Canada's largest energy producers. Both have excellent oil sand and conventional assets, but each has drastically different results as of late.

This conundrum may lead investors to wonder what stock is a better buy today. Here are some thoughts.

Canadian Natural Resources: A Canadian energy legend

Canadian Natural Resources has focused largely on what it is good at: producing oil and natural gas cheaply. This strategy has been very successful. Its stock is up 153% in the past five years and 133% over the past 10 years. Add in dividends and its total respective returns look like 236% and 265%.

With 1.4 million barrels of equivalent (BOE) per day, it is Canada's largest energy producer. Canadian Natural has best-in-class production assets that it operates with factory efficiency.

Canadian Natural has smartly acquired and built out a massive energy inventory. The large independent crude oil and natural gas producer has 33 years of proven energy reserves. It has the second largest energy reserve amongst all energy producers in North America.

While the company had promised 100% of its free cash flow to shareholders, it recently made a big oil sands acquisition. That will slow near-term shareholder cash returns, but it will provide attractive opportunities over the longer term.

Canadian Natural Resources yields 4.8% today. CNQ has consecutively increased its dividend for 25 years. It trades with a price-to-earnings (P/E) ratio of 13.5 and a price-to-free cash (P/FCF) flow of 13.8. It is not the cheapest energy stock, but it's a pretty good bargain for the quality of the assets you are owning.

Cenovus: Cheap but maybe for a reason

Cenovus Energy is more diversified than Canadian Natural. It is an integrated operator, which means it has both upstream (production) and downstream (refining) operations.

Like Canadian Natural Resources, Cenovus has some really high-quality production assets that span across oil sands, conventional, and offshore operations. It produces 771,300 BOE per day. Like Canadian Natural, it has over 30 years of energy reserves.

The thorn in Cenovus side has been its downstream portfolio. It has six refineries across North America. However, they have had no shortage of problems with everything from fires to breakdowns to weak utilization. It acquired these assets just before the pandemic, but it is still working to rightsize and optimize that business.

Unfortunately, that weakness has impacted results. Cenovus has delivered a 100% total return over the past five years and no total return over the past 10 years. Its stock is only up 1.5% year to date.

Now, there is no doubt the company is significantly better than it was 10 years ago. Its balance sheet is in excellent condition and management is returning 100% of its excess cash right back to shareholders. However, it has yet to prove it can make good money from refining energy.

Cenovus stock has a 3.3% dividend yield. It is cheaper than Canadian Natural Resources with a P/E ratio of 11 and a P/FCF ratio of 8.5.

The Foolish takeaway

Canadian Natural Resources is by far the higher quality company of the two. If you want consistent and steady long-term returns, it is the best bet. However, that comes at a premium valuation (albeit it has a higher dividend yield).

Cenovus is cheap and aggressively buying back stock. However, it needs to get its downstream business fixed (or sold). Until that happens, it might continue to trade at a considerable discount to its premium peers like Canadian Natural.