As Aussie stocks continue to slide this week, job classifieds company Seek Ltd (ASX: SEK) shares are down 5% on Monday's session at the time of writing.

This brings losses for the year to 14%, with shares currently swapping hands at $19.25 apiece, a distant cry from the $26 levels in February.

With shares in the red, investors might be wondering whether to favour Seek or fellow classifieds company CAR Group Ltd (ASX: CAR) going forward.

Both companies have strong positions in their respective spaces, but do their prospects differ? Let's break it down and help you decide which might suit your portfolio.

Are Seek shares a buy?

Seek is an online employment marketplace. The jobs market is there to stay (there will always be job openings that expand and contract along with the business cycle). But does this mean Seek will be there in the future?

As my colleague James reported last month, Bell Potter initiated coverage on Seek shares with a buy rating and a price target of $27 apiece, implying a potential upside of 40% from current levels.

Bell says that Seek's $180 million investment to consolidate its ANZ and Asian marketplaces on the one platform could "facilitate 50% group EBITDA margins", a lift of 6.7 percentage points.

The broker also points out that the Reserve Bank of Australia (RBA)'s likely interest rate cuts will "see ad volumes increase", a net positive for Seek shares.

The broker forecasts a 19% compound annual growth rate (CAGR) in Seek's profits from FY24 to FY28.

CAR Group, on the other hand, owns carsales.com.au, an online marketplace for buying and selling cars.

Analysts at Wilsons recently pointed out that CAR shares are trading at a discount compared to their five-year average valuation.

The firm reckons that CAR's "competitive positioning, its pricing power", and "its ongoing margin expansion" give it the edge in the online auto listings market.

CAR's global expansion strategy is another potential growth driver that provides a "long runway" to continue its growth offshore.

It projects CAR to grow profits by the "mid-teens" over "the medium/long-term".

Which is the better buy?

So, which stock should you consider, if any at all? Well, two broker ratings aren't enough to make that decision, that's for sure.

According to CommSec, the consensus of analyst estimates rates both CAR and Seek shares a buy.

Valuation-wise, Seek currently trades at more than 150x its last 12 months' earnings per share (EPS), with analysts projecting a 71% growth in profits by 2026.

Even adjusting for this growth, you're still paying $91 for a dollar of future profits to own Seek shares.

Contrast this to CAR, which sells at 45x trailing earnings, still very expensive on objective terms, which adjusts to 37x after growth estimates.

Valuation ratios aren't a predictive tool, but they can't be overlooked either. Investors should keep this in mind when weighing up both these names.

Seek shares takeaway

Both Seek and CAR have strong growth prospects, but their stories differ. Brokers say Seek is positioned to take advantage of a potential recovery in the jobs market, whereas RBA rate cuts could support car transactions for CAR's marketplace.

The consensus is that both are a buy, so as to which one – it depends on your own financial goals and circumstances.

But none of us have a crystal ball, which is why paying an appropriate valuation or an investment is paramount. That said, both Seek and CAR trade at lofty valuations as I write.