I'd take 1 of the new HOth Turret to 3 of the old AT-ST.
Hell, I traded my AT-ST away from the last Hoth UBP.
I'm down for both of those sets, though I'll probably buy more of the Rebel set than the Imperial one depending on the price... I only have one of the Rebel Turrets, and would like 3 or more (more would be nice). That's an item I've wanted more of since I got the first one, at a hopefully lower price for "army building" it. It's to-scale, fairly detailed (outside anyway). Can't beat it.
The AT-ST I'm into, but the only thing that deters me is that the Hoth AT-ST has pretty significant differences in terms of the two models, and so I'm only into getting one because of that. I cannot fathom them altering the sculpt at all on that, and I have a number of the WM one now, so I'm ok with just one Hoth decoed one I think then... unless there's some huge surprise in that set.