So as we just learned, running up to the vintage of concern we had very manageable default rates. 2003 also benchmarks one of the last year where more mainstream mortgage products dominated the market.

But when looking at a bench mark for prices I prefer to look at the inflation adjusted historic norm.  

The first benchmark I use to purchase says that for a $1000/mo rent my investment can't be over $80,000, and the second benchmark says NOI (Monthly Rent - (taxes/10) - (Insurance/10) - $100/mo maintenance reserve) can't exceed $800.  

Take a peek at the profitability benchmarks for the respective REI markets.I will give you a headline stat to compare the UK-US.

Most buyers and sellers use that 9-10 cap as a benchmark for MHPs.

I do understand that rental properties are a function of appreciation but wish to know what would be the best methodology to understand the overall negative cashflow to asset appreciation ratio or a metric to benchmark it against e.g. % appreciation YoY.

on developing the habits that got you to your 1M bench mark, they say making it to your first 1M is the hardest now is keeping it and growing it. 

Some of the old benchmarks have even been realigned now using satellite mapping.

When I do the fifty percent rule.using those figures, I'm barely at the $100 a door free and clear cash flow benchmark.

When I say it's next to impossible to "cash flow positively" in Brooklyn I mean with a 20% down payment which is the most common down payment and therefore the benchmark for all property analysis for mere mortals (in my eyes at least).