I recently got a Signal Flat Park and I really like the board so far so I'm gonna recommend it.
True twin with no camber, completely flat. It's not as catchy as a cambered board or has that pivoty feel of a full reverse board, a nice happy medium between the two. It's also definitely one of the lighter boards I've hopped on, always a nice plus. The flex is great, super even throughout the board. Pretty darn good pop for it's flex too, it won't send you to the moon, but it's got enough oompf in it that your ollies just feel "right". Finally it has a sintered base; most park boards I see have extruded so this was definitely one of the buying points for me.
I'm still very much a beginner to the park, but I can throw myself off kickers and do basic 50/50's on features. I can see someone who's more skilled in the park just ripping with the board.
I am comfortable going down most any run though, so I'm not a complete slouch of a snowboarder, heh. I was able to bee-line groomers just fine and it was pretty darn fun to take through some moguls. So in all-mountain regard it's good, just without any of those fancy sidecuts more expensive boards have it did have a bit of trouble gripping sections of hardpack that were a bit icy.
Anyways, it's just a down to earth, well-built park board.
Edit: I misread the "more geared for all-mountain part" and just read you wanted something to progress in the park haha. In this case I would say looking at the Arbor Westmark or a Never Summer Proto. Costs more, but have better all-mountain capability while still design for hitting the park.