Refi options for a newbie in South Boston

[Nick DePrizio]

My wife and I own a condo Southie and are currently renting it out while we live in San Francisco. It's Cash Flow positive about $175 a month (which we are putting into principal), Loan was for 328k @ 4.25% and are looking at refi options. Cap Rate is about 5%, COC like 2% but Total ROI like 100% due to market appreciation over the two years we've owned. Looking at the refi options I see generally a 30yr %3.88 that would cost about $250 which we'd recoup in about 2 years in payments. Our other options is switching to a 15yr which would the turn it cash flow negative about 500 a month. Albiet this saves 150k or so on interest throughout the life of the loan etc. We are fortunate to where we have the careers where the property doesnt need to be CF+. What is the general heuristics on situations like this? 30years someone else pays back the loan for us, vs 15years we pay back some faster and get it to a point where there is no more financing when we are 45? Does this change if it's not a refi? If we look to buy another investment property is it just different schools of thought? Obviously if you can get a 15yr and be CF+ thats great but a market like south boston I dont think that really exists.

Thanks in advance- looking forward to growing with this community as we explore this new aspect of life.