Adjustable rate mortgages on investment property

Dear bp family, I want to know how you all feel about ARMs on cash-flowing rental properties. Im looking to possibly do an investment loan on a four family or duplex. The credit union and bank lenders (milwaukee,wi) that i have approached have all offered ARM loans amortized over 20-30 years with 25% down at 4-6 percent on no occupied multi family properties. I personally like 20-30 year fixed products ARMs somewhat “scare” me ! Even though the property will be a cash flowing multifamily. I appreciate ALL of you feedback. Feel free to connect with me !