I know it's late, but I also have been using Cozy.co (Apartments.com) for about 3 years and it works great. I was in a situation where I needed more flexibility and features (I managed a property for someone else), so I opted for TenantCloud.com and have also been using it for over a year. It's a bit more customizable and flexible in other areas too, but of course with that also comes a higher learning curve. Not too bad though, but now I prefer it over Cozy only for that reason. I still have a few tenants on Cozy because I don't want my tenants to have to go through the trouble of switching, but all my new tenants must get a TenantCloud account. Although you can use its free account to keep track of things, the downside is that it costs $90/year or $9/month for a Standard account to enable rent collection. For me, it's worth it for the flexibility and as a bonus I actually ended up making more money last year than this price because of its flexibility with late fee rules. I never enforced it fully in Cozy due to having to manually add the per-day late fees in my lease (just one thing that's more flexible). Also, I have more units now than I had at the beginning, so it's easier to justify the price.
So I'd still opt for Cozy if you don't need the extra flexibility. As far as money tracking, I'd recommend using a proper accounting software. I use waveapps.com (free), but other free or paid solutions might work better for you.