I consider them both in the same category of "not really dress watches" because I hold the notion--the origins of which are obscure--that a true dress watch does not have subdials, a moonphase display, or other obvious complications. My reasons for preferring the 5205G are: larger size, fewer subdials, preference for apertures, more modern design, love the concave bezel, and love the sculpted lugs. As for suitability, I think both work with suits but the 5146 is too small to be worn with short sleeves unless one has a small wrist. Most of these points, as usual, are merely matters of taste, style, and cultural norms.
Park