However, there seems to be more flexibility on DTI with a HELOC. 

There are definitive advantages in making a cash offer:(1) Flexibility on Price - Lower Cost Basis(2) Quicker Close(3) Greater Negotiating Power post InspectionAll of these yield to higher yield with one caveat.

Look for portfolio lenders if they don't resell to secondary market they usually have more flexibility or unique loan programs.

In my opinion, the higher price points in just about any city give investors the most flexibility to see appreciation that is actionable (meaning you could actually sell the house) and cash flow.Sorry for the long response, but I am always fascinated how we as investors can fall into traps of broadly labeling markets or ideas.  

@Kimberly Kesterke  I have a few properties with a few different partners and the common factor is having someone with a flexible work schedule.

I actually think a cash reno would give me the most flexibility in a down market.

Personally, I wouldn't mind having a commercial loan (all my property loans are commercial) to get better terms like a 30 yr fixed rate with more flexibility (like putting it in an LLC).

In the end, they need the flexibility to be able to manage, sell, and market your account.

Will you be flexible if you need to change the plan?  

However with being  an 8 unit and therefore commercial, there could be some flexibility, you would have to ask the lender.Seller financing for some of the DP is somewhat common with commercial loans (I've done that a number of times).