the a frame is an outstanding bullet. the partition is a much older and proven bullet. i really don't think you'd go wrong with either but for up close, sturdiness, the a frame is a stronger bullet because, if I recall correctly, it is also bonded. for me, the partition has been more accurate and really easy to load, but for your shot distances, it doesn't look like precise accuracy is a concern (50 yards).
At that distance, I'd opt for the Barnes TTSX myself. I favor the TSX and TTSX over either of the above mentioned, especially at closer ranges. They blow through both shoulders (as would the other 2 as well) but I really really like the Barnes. The A frame also has a solid copper jacket, so fouling would be no different than the Barnes. At least that is my experience.
I've seen what all 3 do up close on deer and bears. Looking back, the results were all the same: a dead animal. That said, the bears and deer that were killed with the Barnes all dropped at the shot. The same is not true for the other 2 but that really doesn't mean much.
Calibers were 300 Win mag, 270, 300 RUM, 30.06, and 7mm Rem mag.