Comparing the new Iron Press to the Rockchucker is a little like comparing apples to oranges. The Iron Press appears to be Hornady's entry into the "serious single stage" competition arena. Meanwhile the Rockchucker has more in common size and design wise with the Hornady Lock N'Load Classic press. But at just over half the cost of the Rockchucker. Granted the Classic's main frame is aluminium. But for stiffness I'd rank it up there. And after wrestling with a Lee single stage which turned out to be out of alignment between the ram and die station the first thing I checked when I bought my Ln'L Classic is the alignment and trueness of the ram axis to the die station. And it passed with flying colors.
So all in all I would say that if you are looking at the heavier options that go beyond the more or less traditional loop style frame of the Lee, RCBS, Hornady and others then the Iron Press is not a bad item to consider. But along with the Iron Press I would suggest you also look at the RCBS Summit, the Forster Co-Ax and perhaps a Lyman T-Mag. All are in that range of bigger, heavier, stiffer and generally more burly.
When I was shopping for a SS press which led me to buying the Hornady Classic I was taken by the rapid die changes possible with the Hornady bushing system. It proved out to be a lot faster than screwing the dies into place. I've had zero regrets about going with Hornady's press and bayonet style bushings.
If I were to go with one of the other brands I'd likely make sure that the press has the threads for the 1 1/4 size dies and that takes the Hornady bushing conversion. The other option is the pinch lock style threaded die lock rings.
The Lee rubber Oring style still allows movement much too easily and the styles with the set screws bugger up the threads on the dies. And neither one sits accurately flat like the Hornady or similar pinch lock style rings do. The other styles also do not ensure a square positioning of the lock rings. So for use in something like a Forster where only the ring is holding the die in position I'd suggest that the split pinching style lock rings are essential. But the rings cost as much as the bayonet bushings. And the bayonet bushings speed up die switching on any press other than the Forster so much that I'd have to say that it's a slam dunk sort of deal if the press will accept the bayonet outer bushing.