I'm an old house person and indeed I live in an old house. Recently I've been looking for an older rental property but they are mostly shot to bits. So now I'm starting to think of buying a more more modern house, say, built in the last 20 yrs or so. But, I've heard lots of tales that new houses can be poor quality and full of their own defects. What is your advice re buying newer properties. Some building companies must be better than others or maybe there are tell tale signs of cost cutting and poor quality that I should be looking out for?
Thanks. It's not a DIY question I know that, but your input is appreciated.    

Correction, an NHBC warranty IS WORTHLESS...

sorry about that,

but Woodsmith's advice is pretty spot on really,

in my opinion, I would not touch a house that has been built after 1980...(unless of course we built it!! ahem!) as the general strength and quality just is not there..
many of the older rental properties are usually just cosmetically shot.. having refurbed quite a few now.. the biggest problem with them in general, is damp course failure due to using a tar dpc which weeps out due to age and years of heat cycles... but can be rectified..

in terms of new builds, small developments are better, as the quality will be maintained on a "few" rather than a large amount on a quick turn around!!

If you're looking to rent the house out, a modern house is fine IMO - Cheap to purchase, little to really go wrong.

I am more a fan of 1970 - 1990 type houses.