Drawing Hebrew text seems to have gotten much slower in the latest (4.2a beta 2). Scrolling is better in most resources, but scrolling in Hebrew texts (such as BHS) is painful in the extreme - much worse than scrolling ever used to be - almost to the point of being unusable.
I'm running Logos 4.2a beta 2 (4.21.4.8259) on 17" MBP, Snow Leopard 10.6.5, 8GB RAM, Intel Core i7 2.66GHz.