[_ck_]

If you are not on 2.6 yet, stay with 2.5 and install bbPress 0.9

bbPress 1.0 is in ALPHA and not ready for active sites that use/need plugins. Many of my plugins have issues with 1.0 because of many internal changes.

bbPress integration is easy and takes just a few minutes if you have a typical server and standard setup.

There are a several large sites using bbPress (including WordPress.org) so it handles high traffic just fine.

I’ve never heard of anyone converting from Simple:Press, you’ll have to search for it. If you can get it into PHPBB2 format, several people have converted from that.