Apex Predator or Conservationist ?
I am a fan of lower debt, part of the reason for this is going to be various loan limits even if you have two properties with equity it may be better to have one free and clear and the other with less equity to reduce overall risk.
What are your goals in RE? Replace day job income and cruise along or do you want to build high rises and devour the souls of your competition? (:
In your case stated above as you being the apex predator where you're buying as much as you can and leveraging it all to the hilt, you're not actually the apex predator. The apex predator in that case would be the banks that could stop giving you credit, tenants that stop paying rent and/or the economy tanking. What if you're leveraged to the max, have several sizable deals in development and banks tighten up lending/raise rates/the market tanks? Can you afford to complete and hold those deals out of pocket if you can't sell or refi them? Or, if you have to sell, if you can at all, can you afford to sell at a considerable loss if values drop?
The problem with scaling up aggressively is you generally extend yourself more and more and more and the learning curve also doesn't go away if you're taking on larger/different projects that you haven't tackled before, hiring employees, entering new markets, etc. What may have been a slow down or hiccup at a smaller scale can wipe you out in a few months at the larger scale, especially compounded by any mistakes you've made with your new market or larger scale of projects. I love the apex predator attitude but I think, with most models at least, you have to stress test and proceed cautiously if you want to make it long term. I think somewhere in the middle of your two scenarios is likely the right play, at least for my taste.