And your evidence for this is???

The "weird lenders" are largely monoline lenders, many of which are massive companies and have been around for many decades.   A number are even owned by the banks.  

My experience has been that they provide much better service than the banks because mortgages is all they do.    As other posters have pointed out, banks are notorious for providing terrible service and incorrect advice about mortgages.

Awful conditions?  It is absolutely without question that the big banks have MUCH poorer terms for breaking a fixed rate mortgage than monoline lenders who work through the broker channel, with a few exceptions.  So the argument in the article that the banks are better at helping you with the bigger financial picture is a bit rich.

Go to the big banks if you like paying a premium for their stupid ads, massive profits, and 
 enormous branch infrastructure.   But at least learn the truth about this very important financial decision.

No I'm not a broker.