There are no secret negotiating tricks, low ball offers with love letters, or highly intelligent investors from afar that can win bids due to awesome use of language. 

I recently bid on a 10-unit apartment building that was getting below market rents ($320 below current market rents on average).

I could model what held-for-sale properties would potentially sell for and on a weekly basis adjust our model parameters based on what winning bids were for the week.

So my personal take: If you feel like having a non-contingent offer will allow you to be more competitive and save $10k+ on the new home because of a bidding war/multi-offer situation, then it may make sense. 

The brands I've been bid on have been:Eco WindowsCGI Sparta SeriesLawson IndustriesESWindowsAssuraAssura is from home depot, main advantage i've found is that they have a quick lead time of 4 weeks, compared to everyone else saying 6-8 weeks.CGI I heard its a reputable brand with a good warranty Lawson, cheapest quote but Im' hearing has a huge lead time now and they have been messing up peoples orders with sizes or specificationsES Windows, comes from Colombia and I heard spare parts, replacements and customer service is terribleEco, I haven't really heard much about but price seems close to what I'm being quoted for CGI Spartas Anybody on here with more experience that can help me narrow it down? 

I’ve been investing in the Tampa market for over 20 years, and in just the past year, I've bid on several mid-size apartment buildings and at least a dozen duplexes.

Get multiple bids as anything else

I have googled and found a few law firms that actually seem to specialize in this and have listings of houses that are about to go to auction or already have bids that will be granted before the date someone can offer a higher bid. 

There is nothing here that seems unreasonable, I would push back on the $75 in person service, and I want 3 bids on every reno project if they're charing 12.5% to manage.

Get bids on the removal and cleanup, and compare that to a buyout amount.