My iPad default browser is Safari. What factors would influence me choosing a different browser?

The reasons for selecting one or other browsers is largely a matter of preference - or platform-specific functionality.

For many, Apple Safari is both adequate and preferred as it is both tightly integrated with iOS/iPadOS and is heavily security/privacy focussed. If you are exclusively working with iPhone, iPad and Mac, you may never need an alternative browser.

By contrast, you may have need to use Google’s wider cross-platform functionality - and access to web/service credentials that you have entrusted Google to keep secure. If you trust Google (!) - or you work for a business that uses Google Docs as an enterprise tool - then the Chrome browser may be a good fit for your needs.

There are other alternatives, each with their own unique feature set. Firefox, for example, is similarly security/privacy focussed. As a primary (or additional) browser, Firefox may also be good choice - in particular if you work with other computing platforms such as Microsoft PC and/or Mac.

Speaking for myself alone, when working with iPad I find that Safari is my go-to primary browser; as a secondary browser, for those few occasions that a on older website doesn’t best accommodate Safari’s advanced security features, my fall-back is Firefox.

The best browser for your needs can only be determined by you. If you are new to iPad and the Apple ecosystem and don’t have an predetermined need for an alternative, you might be well advised to use Safari and learn its strengths. If it doesn’t work for you, then look at alternatives.