I am a huge fan of staying in the family of products and would personally use Blackfire with a BF LSP, Pinnacle with a Pinnacle LSP, etc. Consider this is just my opinion and practice and by no means a dictate here to those who practice differently.
That being said, i absolutely LOVED P21S GEPC before any carnauba LSP's i used to use.
Shortspark, i have been wanting to try the DG Squeaky Clean product however cannot find it anywhere larger than a 4 ounce bottle. Even talked to Duragloss folks and they only showed it being offered in that size.
My favorite "universal" paint prep product nowadays is Car Pro Eraser. Sure, it's not a machined paint cleaner and is a MF wipedown step i do just before my LSP's but i like what it does. While that may go against my principle of "staying in the family" as i'm not using Car Pro coatings (yet) it works well for me as i use a few different LSP's.