While there is no universal answer to this, small business or a startup often has business process that is subject to evolve (less defined business process) and rather needs a flexible solution that is easy to customize and change.     Very small business often works best with excel spreadsheet (easy to change), for example.

With users from 10 to 100 persons, the company should expect that CRM software can offer well-defined process and workflow that users can follow through in the CRM systems.   Business manager should also be able to utilize business reports in both predefined formats and ad-hoc analysis/discovery from the CRM systems.

User security management and data audit is also important where companies need team member to be able to access customer data only on need-to-know basis.

For large business especially multinational corporations, global CRM software solution providers that can respond through different timezones and languages will become a better choice.    Often these global providers also work with (large) consulting service companies that can supply workforce across different countries to work in the software implementation.

Nonetheless, for consideration of budget and flexibility, many large multinational businesses have also chosen to adopt local CRM software solutions or even an open source software solution with lot of customization and provide own helpdesk support for its international user community.