I agree with working with an agent only if you're super busy and need the Errors & Omissions Insurance just in case. If you have some time and don't mind doing marketing and showings, you could handle the sale yourself- but that's not for everyone. Do you have accurate P&L statements and a proforma or anything? Have you been self managing? If all of your financials are in order I'd definitely start marketing that right away. What's your reason for selling now btw? Just so you can move? Have you run the numbers and it makes sense to sell?
Please let me know if I can be of any assistance - Private Message me and I'll send my contact details.
I have managed a $135m portfolio of investment properties (multifamily, office, retail). I asset managed a mixed use building in Oakland that had 4-5 STR but I promptly turned them into longer term rentals due to the property management company eating most of the profits.