So eventually this negative cash flow property becomes cash flow positive and pays for itself including property taxes, hoa, mortgage etc.Trying to calculate how bad is my investment here or should i sell out if there is appreciation 

Generally speaking, Boston proper is an appreciation market (low cap rates) unless you have a solid value-add play.

Next, speak with a lender and find out what you can afford.

When I checked their reviews, I first started with the negatives ones and they were similar to the ones found on Reddit.

I recently had a conversation with a Russian-speaking realtor from Ohio and wanted to share some insights:Competition among investors is very strong.

Quote from @Fiona Brown: LOL @Chris SeveneyHe has picked who he wants to deal with So I thought I would ask as I cannot find ANY reviews... and I have picked mine :) Which is you LOL as I found heaps good reviews for youWe have a call with your associate tomorrow for my pick at 10 am Not sure who we speaking to as 2 people have emailed the times Katie KlezekToni Shackelfordok, I am blushing... 

I've heard this guy speak, he's a smart guy.

Listen to podcasts, read books, and if you plan to invest in the Netherlands find some resources that speak to that market specifically.

I realize it's just an example and my comment is a generalization but just something to be aware of.With regards to the original question, I think it comes down more to what you want to do and what the offer is for walking away vs. rebuilding.That is the exact example a public insurance adjuster used when speaking to a local investor group a few years ago.

I'll be happy to speak with you if you want to know more.