I can offer my opinion and experiences....
....we also have a Lagoon450F, and we also have the hardtop
bimini and full enclosure.
In general, I love the flybridge from the first time I experienced one and have ever since. The visibility up there is just incomparable to the monos I had before and compared to the raised or corner cockpits I have tried. You can see
fishing pots so much more easily,
water color changes, everything. With the operating "sunroof" you can get a decent view of the port aft when
docking as well. As for seeing around the headsail, it doesn't seem to be an issue to me.
The stairs on the L450! Huge difference. I recently helped deliver a L500 400nm in 47 hours, a great fast boat. But the L500 had totally exposed stair access to the flybridge and relatively low
lifelines, I actually felt nervous transitioning. But with my L450, I can easily go up and down with a book in one hand a drink in another and get my balance with my hips on the inside following stairs. A subtle detail that I didn't appreciate when I bought her, but huge in my mind now.
We originally had no
bimini at all. That sucked from just plain too much sun. Then I got the soft binini. Still sucked, it never maintained its setup as firmly as I would like and had to be adjusted too often. Also the
wind and spray to windward were always present.
Then we got the glorious hardtop and now with the wrap around enclosures. Amazing. Truly amazing. Recently we were going to windward with 25-28 kts apparent, and I was thinking huh? Seems calm. Then stuck my
head out. BLAST! Oh yeah, that enclosure! Now going to windward is if anything too comfortable.
All the sail controls are right there on the L450. It feels super secure up there. We have our jack-lines permanently laid out, and have practiced using them. But we have not felt the need to actually put them to use. I have had too many hours slamming the boat to windward in moderate seas, and she was still very comfortable. Only once was I a bad
captain and went 40nm to windward against 4m+ seas, and that was terrible. Turned around and headed back, and it was magically calm and wonderful sailing along with the waves. Perhaps I should have used the
jacklines then, but on the L450, going from the cockpit to the flybridge on stbd, there is no way you are going to fall of the boat. Still, we have the
jacklines and harnesses ready, in case conditions merit.
-Erik