There are lots of differing opinions about Columbias and other production glass boats from that era. IMHO, the story is told by the number of them still out there 40 and 50 years later - they must have done something right.
I own and have been restoring a 1970 Columbia 43 so I know every inch of the boat. For the most part they used very high quality gear - solid bronze, roller bearing turning blocks in 1970? State of the art. Stainless steel genny track, an elliptical mast extrusion - again, state of the art back then, bronze turnbuckles, stainless Barients, top quality electrical panel etc. The wiring was pretty poor - strung directly to the fittings between the liner and deck or hull, lots in the bilge etc. Gate valves were near universal back then except on the very highest quality offshore boats. They did save by using a cast iron keel on most of them, with steel channel backers which rust away but at least they weren't glassed in place - many builders DID glass in steel structural supports.
The glass work is the equal of most boats back then, not vacuumed but not sloppy either. It has never had a blister but I have experienced some areas of top skin delamination on the deck - polyester resin & plywood will do that, especially if hardware sealing is not maintained.

It is not overly heavy either - the boat was regarded as suspiciously light for offshore use back then but it won it's class in the Transpac. The gel coat is very high quality, after 41 years I can buff it until I can read other boats names in the reflections.
You have to remember that this was the era when huge numbers of people were being introduced to sailboats so the general level of knowledge of what constituted quality was pretty low. I think a big part of the rep (or rap) that Columbia got was due to the fact that they were in at the start of full plastic liners. This was the era of the flower people and "plastic" was the utilitarian pejorative of the day. The general view then was that the interiors of the Leaky Teakies was the epitome of quality and the liner interiors were cheap - the construction equivalent of arborite and particle board.
I have found my Columbia, and the others I have known, including a 57 (gorgeous boat!!) to be good, production quality boats and, as I said, look how many are still around. Comparing their build quality to current boats or boats from much later eras is absurd - would you expect a 1970 Mustang to be built as well as, or perform as well as a current one?