This isn't to say that every company, project, or use case requires the most expensive cameras or full production crew. In some cases, a more "authentic" aesthetic is appropriate, though even in these cases there is often more happening behind the scenes than one might think.
When evaluating a portfolio, there are many things to look for, but here are a few crucial ones:
1. Image - Does the work look like an ad you might see on television or in a movie? Is the footage sharp? Is there depth to the lighting and does it convey an appropriate mood?
2. Audio - Does the audio sound well balanced and clear? Are there distracting background noises during interviews? Does the music fit the tone of the piece?
3. Editing - Are there jarring or cuts or blatant errors in the edit? Are transitions modern and tasetfull? Does the pacing feel right? Does the editing support the emotional message?
4. Design - Are fonts and colors consistent and on-brand? Are graphic design elements sharp and high-quality? Are design elements distracting or helpful?
A poor video can do more damage to your brand than good, so judge portfolios carefully
Most production companies will be happy to set up a conference call or even meet in person to discuss your project, which can help you get a feel for the personality of the team you'll be working with and help refine the plans for the project, which results in a more accurate quote. Keep in mind the that crews can have very different personalities and styles, so try to find one that matches the culture and environment of your company or project. One thing to note here though - counterintuitively for some corporate employees, many of the best or highest-end production crews will not show up dressed like an AV team you would see at an event. Creative videos are made by creative people, and unless it is absolutely necessary, most will not be wearing matching polos or similar. This is also for practical reasons. Most crew positions are hard, manual labor that is typically a much longer work day than an office job.
The first we'll call Tier 1. This level of quality is for projects like national brand advertising, corporate external video like product launches, or any high-profile placement where quality is paramount. This level of production can easily break into six figures or more, depending on the scope of the concept. A set at this level consists of a large crew, sometimes as many as 30+ people, along with large equipment and lots of pre-production. A shoot this size almost always involves union cast and crew, and extensive post-production that exponentially raises costs. Production companies operating at this level usually contracted through an advertising agency, though not always.
Tier 2 would be things like regional advertising, internal corporate video, external and internal video for medium size companies, and most independent films. Quotes for these projects can vary wildly, but you're likely to recieve estimates in the 10-60k range depending on the scope of the concept and team you're hiring. This shoot might be a crew of 3-10 and slightly less expensive gear, though the results can still be incredible with the right crew.
Finally, Tier 3 would usually be use cases such as local and regional advertising, corporate event coverage and internal video, or medium and small business web advertising. You can expect to see quotes ranging from 5-25k at this level. Quality here varies massively. Some start-ups and up-and-coming companies will produce content at the level of Tier 2 and even Tier 1 projects in this price range. There are also companies operating at this budget level that are unreliable, or produce content of objectively poor quality, so it pays to take some time to compare portfolios and quotes.
Within these tiers, the end price depends on factors such as number of talent, size of crew, quality of equipment, number of locations, number of shooting days, and complexity of post-production. These are best decided on in collaboration with a producer or project manager, so if possible always try to have a conversation with someone before getting a quote. Make sure your expectations are clear and the company is capable of providing the size of production that you need.
As with anything, you (usually) get what you pay for. It's definitely possible to find unbelievable deals, especially in the lower tiers where newcomers are eager to build their portfolio, but don't make the mistake of taking the lower quote at the expense of quality.