Pretty decent, actually. Although they are very big boats, the hull/beam ratio is pretty good (relatively narrow hulls, which is why they did the transom extensions, considering the overall weight of the boats). They are luxury cruisers, with an emphasis on the luxury, but will put in good daily averages.
We know one of the skipper/instructors of "PDQ U", the training course PDQ used to do for new owners. She really liked them. Putting them in relation to other, similar sized cats, they would be close to the Lagoon 440
and 410 (two of the better performing Lagoons). Not as fast as a St Francis 44 or an Outremer
I was on one only once, but it wasn't a great sailing day due to light winds. That is one of the issues I had with it; it takes 10 knots of wind
to get them moving. After that, though, all is good. Personally, I didn't care for all that freeboard, but it does mean a high bridgedeck. (As a St. Francis owner, I opted for the other side of that compromise; I'll take a few more wave slaps in order to get better windward performance. It's a decision you have to make one way or the other, depending on your personal preference.)
Well made. Not cheap
Hope this helps.