Although quirky, I do really like the Fuji and the prime's offer quality and speed, but are more expensive and bigger than the Limiteds, which I also lust for. But, I've decided, for now, against making any move. One reason is timing - Fuji has a huge sale and new prices are close to what used prices were two days ago. Another reason is I need to step back and make sure I make a more rational choice
One con against coming back to Pentax is still AF speed, while it is good for most of what I do, I do enjoy bird photography (when I have a proper long lens). While the CAF is better in the K3 series than my former K5II, from what I've read, it still lags, substantially, from Canon or Nikon. But I much prefer the Pentax ergonomics. One thought is to keep the Fuji for my main kit, but add a DSLR with a long lens for birds. I was looking at the 150-450 while contemplating Pentax, but now I am sorely tempted to get a D7000 body (same sensor as K5II) and Nikon's new 200-500 5.6. That combo is cheaper than the Pentax 150-450, but since the lens is not yet out, it is unknown how it stacks up optically. I've also thought of a 7D and the venerable Canon 400 5.6L, but not too excited about that camera body's higher ISO compared to the Nikon or Pentax offerings
There are multiple good choices, and really can't go wrong with any.