The B423, B393, and Catalina42 MKII were on my short list when I purchased the B411. I have sailed them all, extensively.
All are fine boats. And your individual choice would be best informed by the particular boat available to you and your personal tastes. In other words, in the right condition any one model may be the better choice.
The forward head configuration is in my opinion a superior layout. You can't sleep in a v-berth while underway, but you can use a forward head as a sail locker and superior spin-sail rigging area. It is perfect. The B423 doesn't have it. The Catalina 42 2 cabin does.
The B393 seems much smaller than the B411, probably because of the pullman/forward head is where Beneteau took out the 1.5 feet of length. The B423 and B393 share the same Beneteau cabin-top fixed light installations and it is not a matter of if they will become scored and leak but when. Especially if you favor a traditional flaking mainsail. Your crew will walk on those lights and the seals will fail. The Cat42 MKII doesn't have these fixed lights on the cabin top.
The Catalina42 2 cabin has a great galley, and fantastic storage, engine access. You pay for that galley with a saloon that doesn't make into useable sea berths. And the nav-station (a fading design feature) is pushed forward to the mast, where it is in the way and far from the helm.
The Catalina has the best headroom (I'm 6'3") and the most freeboard and higher cabin top - something to consider if you go to sea. The B411 has the lowest cabin top clearance of all - easy to scramble forward. You pay for this with a noticeably more confined interior.
The B411 holds twice the freshwater of the Catalina42, but has half the holding tank volume.
I'm not a fan of the wing-keel, and that is the only way you can get a shoal-draft Cat42. They're a bear to get unstuck from the mud.
All three boats have stout, double-spreader rigs and are available with slab reefing. All have the scoop stern swim platform, unfortunately a fading production design element. None play with the silly twin helm arrangement. All three boats are available with a superior aft galley arrangement suitable for cooking while underway.
In summary, the 42 foot range (B411 & Cat42 MKII) is the goldilocks solution - just right. Fast and smooth motion, especially when the going gets rough. And just small enough to singlehand. Especially so because all the controls are led aft. My preference fell to the Beneteau, she's a sailors boat, great fit and finish topside and below, and the prettier shear. If my wife was buying we probably would have ended up on the Catalina.
