Which one do you prefer?

Potter's no nonsense style or Blake's laid back easy way of handling things?

I prefer Colonel Potter. He may have been no nonsense but he was also smart enough not to expect draftee doctors to be soldiers. As long as they respected his authority as their superior officer he was willing to look the other way when they behaved in a less than military manner.

I preferred Col Potter as well. Henry but let everyone walk over him.

Blake. Not only against Potter, but Blake is my favorite character of the whole series.

I prefer Henry Blake, I always thought he was more fun and had a better personality than Potter.

Blake

Potter could have been a very important character, and I think represents a missed chance for the show - and maybe for the whole sub-genre of issues-oriented sitcoms. He had served under Harry Truman, had been in both world wars, and could have been a stand-in for Truman's views in explaining why the US fought in Korea (or why it was necessary to fight anywhere). In that role, he could have been very much like the Leo McGarry (played by John Spencer) character on the West Wing. Instead, he was limited to a view that the army was his career and surgeon was his job, but those things didn't really have much to do with the broader cause.
That's a thoughtful analysis.

Henry Blake for me, though I liked Potter & Harry Morgan was good in the role.
Too bad they emasculated Potter & made his subject to Alda's heavy-handed & long-winded sermons.

Blake. Not only against Potter, but Blake is my favorite character of the whole series.

I would agree with this.