They are very different boats. Keep in mind the Leopard 44 and 45 are also very different boats. Sailing qualities the H44 is the easy winner. Much better than the L44 and better than the L45. The difference drops as you load the boats up however. The H44 is a very light boat for its length. The Leopards are built like tanks. Part of the Helia weight reduction are very small fuel and water tanks but watermakers solve the water part. Battery capacity tends to be about 25% less on the H44. For overall space the Leopards win but they are in effect slightly bigger boats. Helm stations are fine on both.
The front cockpit is a great feature. I was a big doubter when I first saw the design but love it now. The Davit’s are also fantastic on the Leopards and I have noticed lots of other boats are blatantly stealing the design.
If I did not plan on diving I would take the H44 over the L44 because I like sailing. I would take the L45 over either of the other boats. It’s a great design especially the integration of the front and aft cockpits into the main salon. If I am diving either Leopard wins. I came very close to a Helia purchase 6 years ago but the diving part I could not get past. On the Leopard you can gear up 6 divers and all roll into the water together. When you come back to the boat you can roll out of your dive gear and clip it to the davits. Climb aboard and the davits hoist the dive gear back in the boat!
P.S. The new FP Elba 45 looks like a great boat!