A proper 28ga be that an O/U or SxS must come with a few basic ("inherent" may be another word that could apply here) features such as scale appropriate frame, weight, balance etc. Personal preferences, budget range obviously will further drive the selection process from that point forward as far as an individual is prepared to proceed towards such goal.
At the present time, IMHO, the aforementioned basics of 28ga breechloading double guns start with current manufactures like CZ (the least expensive and they produce both O/U and SxS models). Further up the ladder are brands like Franchi, Browning (read some specific models of Cynergy and Citoris), Fabarm, Fausti, Rizzini, Beretta, CG and so on.
Among semi-autos, Weatherby is offering a (Turk built) 28ga semi for 2011, then you have the Remington, Franchi and the Benelli. Never cared much for Remington

but I've handled the Franchi and the Benelli - both are nice guns inside their own individual realms. However, in terms of overall build quality and design, as a field model, I believe the Benelli Legacy 28ga has no other semi competitor in NA at this point in time.
Admittedly, I have no favourites to speak of, well, at least as far as firearms (including shotguns) are concerned mainly due to so much diversity available....my loyalty, however, always rest with something that has the correct attributes i.e. in terms of configuration, balance, handling and most importantly gun fit.