Krusty...
I found the HUGE difference in spring action a major relief when I moved from the 45 to the 52. I was always frustrated with the 45, but immediately loved the 52.
For me, the 45's tighter springs meant jerky motions in close, even with tweaked software settings. In the center, all was well...but when i reached the edge of the spring action I'd have to increase the pressure to get the spring to move. As soon as I go the spring to move, it kicked a good distnace...so smooth control was very tough.
On the 52, the springs are silky smooth, dont affect movement at all.
The other differences ae minor. The trim wheels are tighter and the center detent is subtle on the 52, so its a bit harder to use them for manual trim. The LCD display isnt all that useful, although I didi program it to show time in London and Tokyo, just for kicks.
Not sure about durability on the 52, but I went through 2 X45s in 15months when the view hats lost a direction.