CRM is the ultimate "it depends" question. There are hundreds of solutions out there, and many of them are pretty good. With that said, many fill different niches and have varying strengths and weaknesses.
For basic CRM needs, here's an underrated one: ActiveCampaign. Very inexpensive, easy-to-use, and fully built in with their marketing automation, email, and SMS solution.
It depends on your budget. If you have zero budget, you can use something super simple and basic like Trello or Google spreadsheet. That's what I started off with and then slowly move up to more advanced CRMs like Pipedrive.
Personally I'm a fan of Streak. All CRMs will have their pros and cons, but you have to find something that you and your team will be comfortable with.
