I rarely, if ever, use raytracing and can get quite professional firefly results.  The worst thing you can do is crank up all the settings if you aren't using elements that take advantage of them.  If I'm not using true reflections or certain lights there's really no need for raytracing to be on.

P7's better management of textures (texture tiling and so on) should really help with large scenes.

I completely agree with Gareee and others - you really need to understand what all the render settings do and optimize them for your system and your needs.  There aren't that many in comparison to other renderers.  Of course, you can always save different render presets too.

Stewer has a lot of the settings outlined and there's bits of information all over the place for firefly:  http://www.keindesign.de/stefan/poser/firefaq.html

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