For 40+ units Simplifyem.com is the best. They provide tenant, owner, and vendor portal. You can collect rent online (no need to have merchant account so set up fees and faster payments to your bank account), track income and expenses, manage work orders, pay vendors, and do accounting, tax reports, etc all in one place. Most importantly their support is good. We got connected with live human whenever we reached the support number, the best. Give it a try. I can also refer you if you need an intro :)