There a few 'camps' when it comes to mills, specifically column type. I would recommend researching this a bit because you may fall into one or aspire to another, but maybe you just don't know it yet. This is probably why opinions vary.
Round Post Satisfied Camp: have accepted that raising/lowering head means potential loss of same/exact quill center reposition. This can be somewhat PITA if you have lots of repetitive features for example a simple series of holes, which requires different tooling lengths (short spot drill > medium pilot drill > longer tap assembly > short countersink). But same deal for endmill holder, boring head... So they either have a measurement confirming technique ,which takes more time. Or have made some kind of secondary machine modifications to stabilize the head position through the up/down travel (fabrication).
Round Post Unsatisfied Camp: find the constant adjustment checking or workarounds are not to their liking or work accuracy. They now wish they had a dovetail.
Dovetail Camp: rarely complain about this aspect, the head is locked within the accuracy of column & gib. They just complain about wanting a bigger dovetail mill. LOL
I recognize that within certain machines sizes or price levels, not all options are possible.