We went with the methodology of consulting the family member who we knew was the wealthiest, almost entirely made from property. He had about 3M behind him and was a total guru in our eyes.
First prop was an IP. The wife and her Uncle chose it. I never saw it, just paid for it. Ended up being a dog and we later shot it.
Second prop was an IP. Myself, the wife and to a lesser degree her uncle chose it. It was a dog from the start and never recovered. Shot that as well.
Third prop was a PPoR, later to be an IP. The wife and I both liked it, big triplex block, good bones, horrible garden, divorcing Vendors. Wife's Uncle was consulted yet again and strongly advised not to buy it, said it was a dog. We bought it anyway and have keep it ever since and it was a good decision.
Ran the Uncle off and surpassed him years ago.
The rest up until recently have been decided upon by myself doing the research, and the wife taking the position of throwing negative what-if scenarios at them. If they die during her onslaught, the deal is dropped......if she cannot pick holes in the deal, it survives and we proceed.
This method has it's drawbacks however, as the muck thrower needs to know what s/he's talking about to be able to throw intelligent muck, otherwise you get into all that touchy feely stuff where all rational thought goes straight out the window and you are left with nothing.