I use Manley frames and apart from the fact they get gummed up if they are not stuck close together I like the ability to suffle/slide frames about so that capped frames are at the ends of the super and frames to be filled are at the center. This bit is not quite as fiddly as when supers are castellated.
However, prising frames apart for extraction can be a sod at times, especially when the propolis sticking them together is cold.
Gavin,
>Hoffmans for me in the brood box though - less squashing of bees and easier to prise apart for inspection.
Opposite for me...I find Hoffmans more of a fight in a brood box as they seem to get gummed up more. There's a smaller area for gluing things up with plastic ends, and the frames come out of the box more easily, especially when the temperature is cool. That said 12 hoffman frames in a brood box is alleged to give a faster spring build up as the combs are closer together, and plastic ends dropping off when frames are new can be a pain.
Time's the most important thing, and your decision on what's best for you will depend on your bees and their love of propolis!