The guys working on the Camino Browser have released their second alpha for 0.9. Looks like the slow textbox issue is all but gone now, which is great since I am writing this from within Camino. I think I'll switch over to Camino for the time being and leave the Safari camp. There is a very noticeable snappiness in rendering in Camino when compared with Safari. And, if you do try Camino, don't forget to get Camino ExtraPrefs which will allow you to tune Camino and change the default search engine.