Integration (or the lack thereof) is the fatal flaw in many organizations' deployments. I have faced this with most clients needing to realign their internal Systems-Processes-Personnel issues. Zapier is a powerful integrator but it can also be something of a band-aid solution. Something largely overlooked is that most CRM tools are elements within a wider enterprise solution. Generally, they work well with their own allied elements, okay with some 3rd parties, and not a all with others. The CRM company's overarching ambition is to win you over to their complete suite. Nothing wrong with that if it fits, but you should go in with eyes wide open.

To your question, I have experience selecting and integrating a range of CRM solutions across a variety of industries. In choosing, there are five metrics I follow when considering a CRM application for general use:
1. Organic Fit - To what extent does its underlying methodology fit your existing process. Will it integrate with your other systems (e.g. Accounting, HR, etc)? If not, what would need to change?
2. Market Penetration - If it's widely adopted, others are finding it useful and it's likely well-supported. But there is a reason it isn't #1 on my list: it needs to fit your operation.
3. Quality of Support - Near zero downtime, rapid response to user issues.
4. Scalability - Today's need will not be tomorrow's. What is the existing ceiling? What happens when you blow through it?
5. Cost of Use - Services are not the only things that scale. Write this into your game plan.

The top six examples (in no particular order) would include: Salesforce, Hubspot, Microsoft Dynamics 365, Zoho CRM, Pipedrive and Sugar CRM. Let's arrange a call if you would like me to provide rankings based on above five factors, and I can offer deeper insights to the points raised above.