Having used 3dStudio and similar programs in the past, I'm finding myself frustrated with the lack of direct tools and the unpredictability of orientation in SketchUp. It does have some nice features which have kept me trying to learn (e.g., styles, ability to easily create/erase lines/measures etc) - but some of them remain unpredictable to me (e.g., erasing a line sometimes erases the line, sometimes a wall, sometimes half and object...even when the line was a copy and past from one erased successfully in a similar location 30 seconds earlier).