My weakness is I'm too nice and that has cost me $$$ over the years. In particular I was too soft on late rent and property damage repair fees and it snowballed from there. Solution: an automatic online rent and fee collection system. I manage everything else myself for my small number of properties. I send certified letters as necessary and let the online system collect payments. I investigated about 5 different systems and Innago was the first I came across that fit my need. The other four only allowed for a one time late fee. Some didn't even add the late fee to the current amount due but to the next month. In my opinion with a system such as this, once the tenant is late, there is no further motivation for a tenant to pay other than threat of eviction. I recently started using Innago as it allows for a daily compounding late fee. I have configured it to start on the day I choose and it ends after X number of days. It costs me $2 per property per month. In fact, it can have multiple layers of fees if that's what you want. The problematic tenant has started to shape up. Before the system, always 1 to 2 weeks late. Once implemented, 10 days late the 1st month, 7 days late the second month, and 1 day late last month. All late fees were automatically billed and collected online. Yes, I realize I should have not it get like this in the 1st place and if this effort doesn't pan out, then they are gone.
Innago also has a feature to only accept payment in full including all fees and expenses. No more partial payments. Another win.
I previously allowed Zelle, but with an untrustworthy tenant, there is no partial payment protection. A tenant can send me $5 and as Zillow automatically accepts it, here in AZ, it would count as me collecting partial rent and I would not be allowed to peruse eviction until the next month assuming I didn't disable Zelle and allow this to happen again and again. Also Zelle doesn't allow for the ability to individually enable/disable a tenant in the system.
Money orders require driving over to pick up, or the tenant sending them late and then the late fee issue is still there. Same with checks and cash.
I checked out some of the above mentioned apps and they definitely did not fit my need or were expensive compared to the competition. If you want them to handle applications and contracts also, check out their capabilities and what you as a landlord will need should there every be a problem and a day in court. Zillow applications are one example of a poor implementation. Data the applicant enters seems to frequently not be verified and it allows for complete omissions in fields and hides important information such as social security numbers from landlords. Its unusable. I love Zillow for advertising the property though.