I Personally would rather see better deals. A lot of deals I see on market don't cashflow. No investor, myself included, wants to purchase a property that doesn't make money. Rental properties are after all an active business and no business can survive banking on projected appreciation or some Pro-forma thats on the listing. Thats market speculation and that's never a good strategy.
Both matter but I'd argue deal flow first — you can filter for quality once the pipeline is full. Hard to be selective when you're only seeing 2 deals a month. Volume creates the reps to know what good actually looks like.