The whole point of owning a MHP is so that you don't have any maintenance, such as clogged toilets, appliance repairs, mechanical system repairs.

Additionally there is usially neglect, defferred maintenance and in some cases intentional damage caused by the departing owners/tenants. 

You will have basically no cap ex or maintenance expense and will be able to raise rents by the time any of these expenses start.

I appreciated that their pricing packages were customizable to what you need as a combination of their PM software, maintenance coordination, leasing services, and/or delinquency assistance.

This has served us well for decades because floating rate debt allows us to escape yield maintenance risk, but the tradeoff is we must accept interest rate risk (I wrote an entire article on interest rate risk vs. yield maintenance risk so I won't rehash here). 

Do you enjoy the security of your cashflowing duplex that doesn't need much maintenance?

i'd say it's 2-10 years depending on the property type, how much you put down, how much maintenance you have, etc. 

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But it may save some time and energy to deal with SFH maintenance? 

Common fees will include a set-up fee, a leasing fee for each turnover or a lease renewal fee, marking up maintenance, retaining late fees, and more.