Hi Asaber, where i sail out of, we have a whole bunch of Taipans, one blade and a couple more blades coming soon. With regards to your question, let's see
Design wise, I think the blade has more volume and more freeboard than the T4.9, so it sits higher and seems better suited to heavier crews. Being a newer hull design i think it's a little faster than the T4.9. Not to the extent of knocks your socks off faster than the t4.9, but I think due to the ability to "plane" the blade seems to have that edge. Also, it seems like the blade tacks a little easier due to less hull immersion.
However, from my personal observation the speed difference between the two hulls is at a level where one good tack or a good start or effective shifting of gears in one gust on the T4.9 would probably negate any speed difference between the 2 hulls designs.
I'm not going into rigs because the blade and t4.9 here uses the same rig, so there's not much to talk about. We use a mixture of Goodall and Ashby sails with my peronsal preference for the Asby sails as they seems a little mroe forgiving. Both use the same spinnaker launch and retrieval system here, which makes the spinnaker suprisingly easy to launch and retrieve. Build quality, both are equally great, although both are racing machines and I don't think they are the type of boats you want to drag up the beach if you can help it.
I think the main question you want to ask is really who has a better dealer network closer to you, and which one is easier to get spare parts for. Hope this helps.
