Not bad - but I wish there were tons of ManaxRegina  but there's almost nothing - 2 not great doujins and no fan fics - a few good images is about it :(  
They have to be one of my fav precure pairings up there with NagisaxHonoka & LovexSetsuna.  I don't think any others came close to saying they loved each other as much!  
I dunno why some pairings - like Hibiki x Kanade (never liked them that much) get loads of doujins but others hardly any - especially when Regina is so cute & they are both SO hung up on each other!  Mana is also one of the best modern cure leaders!